Zen of the 100 Yard Zero

[Failure2Stop]

The topic of zeroing comes up quite frequently, and to ease explaination I wrote the following to more easily illustrate my preference and the reasons why.

You might want to take a look at Molon's thread about zeroing:
AR-15 Zeros and Trajectories (https://www.m4carbine.net/showthread.php?t=65679)
to get better acquainted with the nuances in the path of trajectory. Be advised, how something looks in pure data form is much different than real life application.
Recently, Larry Vickers put his thoughts on it in his "ask the SME" section here at M4:https://www.m4carbine.net/showthread.php?p=1329607#post1329607
Anyway, without futher ado, here it is:

The Zen of the 100 Yard Zero

Concept.
I find that a 100 yard zero is the easiest, most intuitive, fastest zero for rapid engagement of human threats at the most applicable envelope of 5.56 employment (0 to 300 meters) with the use of common optics. I use a modification of the 100 yard zero for iron sights, as the sighting capability of irons is different than that of an "open view" optic, since the front sight post will make hold-over at longer ranges a bit more difficult when focusing on the front sight.

First things first, this is based on the use of small caliber, high velocity cartridges (5.56mm or similar) fired from an AR type weapon (or any that place the line of sight through the optic at 2 to 3.5 inches above the bore). Should you be somewhere that measures in meters, 100 meters is effectively identical for the purposes of zeroing.

When the optic is adjusted to place point of impact at the point of aim at 100 yards it greatly simplifies close-range engagements. The trajectory of the bullet will never rise higher than the line of sight, and the path from muzzle to the zero distance will be "flatter" than any other zeroing scheme. What this means to the shooter is that hold-overs for close range shots will be more similar across more distances than any other trajectory. The differences in trajectory are lost on many that do not adhere to high precision standards. Hitting an 8" circle with consistency at 3 to 25 yards is not difficult; hitting a 3" circle across that range spectrum is a bit more technical in nature. The ability to consistently hit that 3" circle is heavily dependent on the shooter being intimately familiar with the amount of hold-over his sights require to place the shot where he wants it. A good shooter that knows his hold-overs will be able to achieve those hits, regardless of zeroing method. The 100 yard zero enables the shooter to use more broadly defined hold-overs with a lower necessity to accurately gauge distance.

With M193 from a 16" barrel with a 2.8" line of sight over bore (common lower 1/3 cowitness), here are what hold-overs commonly come out to:

Holding at the top of a 3" circle will place the round in the lower 1/3 of the circle at 3 yards, and in the upper 1/3 at 70 yards.
Holding in the upper 1/3 of the 3" circle (1 inch high) will place shots within the 3" circle from 30 yards to around 200 yards (though most shooter/weapon/ammo combinations will not be able to maintain that level of precision past 75 yards or so).

http://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi1.jpghttp://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi2.jpg

One can be more precise with the 3 to 50, of course. Giving the shooter a 1/2 inch leeway in trajectory, here are what the holds look like:
2.3" high = 0 to 25 yards (2.8 inches to 1.8 inches strike of round below line of sight)
1.3" high = 25 yards to 55 yards (1.8 inches to 0.8 inches below line of sight
POA/POI = 50 yards to approx 175 yards (1 inch low, zero from 90 to 140, and dropping to 1" low at 175)

http://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi3.jpghttp://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi4.jpghttp://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi5.jpg

Here's what holds with the same 1/2 inch leeway look like with a 50 yard zero (similar to a 200 yard zero):
2.3" high = 0 to 16 (2.8 inches to 1.8 inches low)
1.3" high = 16 to 34 (1.8 inches to .8 inches low)
0.3" high = 34 to 55 yards (0.8 inches low to 0.2 inches high)
0.7" low = 55 yards to 80 yards (0.2" high to 1.2" high)
1.7" low = 80 yards to 120 yards (1.2" high to 2.2" high)
2.7" low = 120 yards to approx 190 yards (2.2" high, to max of about 2.5", back down to 2.2" high)

So, it should be pretty easy to see what zero requires the least amount of thought to get to work with the same level of precision. Further, an error in distance estimation (which is going to be pretty hasty when under stress/facing a lethal threat) is less of an issue with the more gradual rise of a 100 meter zero.

Mid-range work with a 100 yard zero does not suffer once the shooter becomes accustomed to drops and holds.
For all but the smallest of targets, the user of a 100 yard zero can hold POA/POI out to 200 yards (less than 3" of drop).
From 200 to 250 yards, you will have less than 7 inches of drop.
At 300 yards you will see about 12" of drop (about 1 mil for those shooting mil-based reticles).

http://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi6.jpghttp://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi7.jpghttp://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi8.jpg

Shooting past 300 or at targets smaller than 8" circles will require the shooter to become more intimately familiar with firing conditions.

Iron Sights.
When it comes to irons I prefer to zero 2 inches high at 100 yards. This is primarily to maintain awareness of the target at distances that would otherwise obscure the target with the front sight. Since iron sights require the shooter to focus on the front sight for accurate placement of shots, it is difficult to see what to shoot at as distance increases. The trajectory is very similar to the 50/200 zeroing scheme, but a 50 yard/meter zero still leaves a large margin for possible error in adjustment; zeroing at 200 is extremely time-consuming unless the target can provide rapid feedback without requiring the shooter to cover 200 meters to check his groups, and wind begins to make a distinct effect on the bullet at 200, which can cause a lot of issues with deviation adjustment.

Execution.
Zeroing at 100 yards (regardless of POI in relation to POA) removes a lot of "slop" in adjustments, virtually all sight adjustments are referenced at 100 yards/meters (which makes adjustments easier), wind only slightly effects the POI, and it gives the shooter time to hone fundamentals at a distance relevant to the prone position.

Attempting to zero at distances closer than 100 yards in an attempt to achieve a 100 yard zero without actually shooting at 100 yards is no substitute for the real thing. Zero can only be truly achieved by shooting at the actual distance.

There is much gnashing of teeth about zeroing targets. I prefer to use simple targets that have multiple purposes. The B8 pistol target reface is perfectly acceptable for zeroing, though a target with an easily identified center and a grid pattern relevant to the sighting system adjustments makes things a little easier. For iron sights and 1X optics I like a 6 to 8 inch circle for zeroing and confirmation purposes. For optics with a more traditional crosshair I prefer a target with an “X” pattern, which makes holding on the center of the target easier. The idea is to use the smallest target possible that the shooter can consistently find center while using the sighting system. I used to use black 4” circles for 2 MOA dot optics, but after several serious cornea scratches none of my Aimpoints appear circular enough to use such small targets, thus my preference for larger circles. When properly focusing on the front sight tip when using irons, anything smaller than ~6 inches will be difficult to positively identify and center the sight on at 100 meters: thus my preference for larger targets for them as well.

Simply because I do not accept a zero fired closer than 100 yards to be valid does not mean that one should jump all the way back to 100 yards for initial zeroing. With an unzeroed optic I will begin the process at 25 yards, and simply adjust my group to be approximately 1.5 inches below my point of aim. I will rarely fire more than two groups of three rounds each, as I simply need to “get on paper” at 100 so I can get on with achieving a “real” zero. There is no need for specialized targets or fine-tuning of the sights at 25 yards. Just get close and move back to 100 as soon as possible, as the 100 yard walk cuts into time very rapidly.

Confirming zero:
Once you believe that you are zeroed, you need to confirm.
Slight changes in body position will lead to a shift of the natural point of aim (NPA), which can cause inconsistencies and shifts in the group down-range. We want to iron out those possible errors in sighting as they relate to our zero, and that can only be done by observing several overlaid groups.
Here’s how I do it:
The shooter fires four groups of five rounds each. Between each group the shooter stands up, moves around a bit, and then reassumes the prone position and fires the next five round group. Before commencing firing, and for each and every shot of the group, the shooter must have the discipline to ensure that his NPA is correct.
Once the 20 round group is complete, head down-range and check the group. Do not expect it to be as tight as the five round groups used for zeroing. You WILL throw a shot or two. The important thing is determining the POI of the bulk of your shots, and to make whatever minor corrections are necessary to put that group into the POA (target center).

The most common error in zeroing is shooting too fast or too slow. The shooter should manipulate the trigger the same way as if firing to hit the center of the zeroing target in as little time as necessary. Changes in trigger control will equate to changes in POI.

Conclusion:
The 100 yard zero with common optics works. It permits the shooter to focus on the task at hand instead of worrying about hold-over/hold-under at the distances at which rapid action will save lives. In the quest for simplification without capability loss, the 100 yard zero rules the day.

I am completely disinterested in forcing others to adopt my zeroing concept or in telling anyone that what they are currently doing is wrong. I am simply providing hard-earned data to those that are interested in pulling the highest possible performance out of their equipment.

[Moltke]

Great explanation Jack, posts like this are why I read M4C.

[ALCOAR]

Amen Jack....big believer in a 100m zero on all my ARs except precision pieces which get a 200m zero.

I really hope folks listen to this paragraph of yours if nothing else...

"Zeroing at 100 meters (regardless of POI in relation to POA) removes a lot of "slop" in adjustments, virtually all sight adjustments are referenced at 100 yards/meters (which makes adjustments easier), wind only slightly effects the POI, and it gives the shooter time to hone fundamentals at a distance relevant to the prone position."

I'd nominate this for sticky material....if that wouldn't kill it:)

[Voodoo_Man]

100m zero is awesome.

[davidjinks]

Jack,

Solid explanation and visuals.

This all sounds eerily familiar...except this time I have AC.


I can say from personal experience that this method of zeroing is by far the best I've used.

Having come from the Army 25 meter zero moving to a 50 yard zero then the RIBZ...this method that Jack has explained is waaaay better (At least for me and my uses).

Getting your offsets was cake. Once it was explained, demonstrated and then used its way too easy.

[exiledtoIA]

May I print this out. Your explanation is both shorter and better than mine.
Teaching new shooters is not always easy.
Thanks.

[Failure2Stop]

May I print this out. Your explanation is both shorter and better than mine.
Teaching new shooters is not always easy.
Thanks.

You are more than welcome to use it, just throw M4Carbine.net and F2S a kind word while you do :D.

[Ironman8]

Excellent post! This is what I use as well.

Trident mentioned this, so as long as this doesn't turn into a threadjack (and instead adds to the value of this thread), why would one sight at 100m with a RDS, yet sight at 200m with a magnified optic?

My thought would be that you sight both the same since you will be using holdovers within 300m anyway, regardless of sighting system. If using a mildot style, magnified optic, I wouldn't think it wouldn't be necessary to dial at all within even 400m. Past that, you may have to dial to POA/POI, or you could dial half/hold half. This would be much quicker than dialing every range adjustment and would keep holdovers consistent between platforms.

Correct? Or am I missing something?

[Renegade]

I do not shoot human sized targets. I shoot hog sized targets. I also prefer not to have to hold over, or do all that calculation and stuff you showed. I prefer to just put the red dot on the target and presto, dead hog.

That usually means zeroing each gun at slightly different ranges, optimizing for BBL length and cartridge. In the end, it means no holdover unless I exceed the MaxRange.

A little more work, as each gun is different, but better results.

[LtNovakUSA]

Great post! Im going to have to remember this when I get back out to the Real Army. (I hate the schoolhouse, but its a necessary evil)

[Failure2Stop]

I do not shoot human sized targets. I shoot hog sized targets. I also prefer not to have to hold over, or do all that calculation and stuff you showed. I prefer to just put the red dot on the target and presto, dead hog.


That's what "all that math" shows.
From 0 to 25, just hold about 2.2" high and you are good to go on 3" circles, and really, unless you need to maintain a smaller than 3" shot placement window, you can just hold 1.5" high from muzzle to 200 meters.

I can't think of anything easier than that unless I can guarantee that the thing needing to be shot will only appear at an exact certain given distance.

Really, if you are happy with what you are doing, rock on.
FWIW, I have never heard of anyone that is well versed in the 100 meter zero changing to another zeroing scheme unless for a specific purpose, whereas I have seen users of every other scheme abandon them for the 100 meter zero.

Whatever floats your boat though.

[Renegade]

That's what "all that math" shows.
From 0 to 25, just hold about 2.2" high and you are good to go on 3" circles, and really, unless you need to maintain a smaller than 3" shot placement window, you can just hold 1.5" high from muzzle to 200 meters.

Are you shooting 3 inch targets or human sized targets? I thought you said human in first post.

If you are shooting human sized targets, why hold over from 0-25? Put the dot in his chest, and at most you are 2.8 low using your optic.

I guess it is not the zero distance I am confused about, but why you think you need to hold over vs a human at close ranges under standard battle conditions (sniper etc, I can see need for more precise targetting).

[Failure2Stop]

Trident mentioned this, so as long as this doesn't turn into a threadjack (and instead adds to the value of this thread), why would one sight at 100m with a RDS, yet sight at 200m with a magnified optic?


I personally use a 100 meter base zero on everything.
That being said, for long range applications I maintain recorded data out to as far as I can shoot, in 100 meter increments (or even better in 50 meter increments past 600 yards), so I can dial to a true zero and then apply wind hold.

If shooting at unknown distances it is common to dial to a specific range and then employ mil-holds for stuff at closer range.

Further, if shooting for precision at long range, the mil-holds for sub-200 are pretty easy (and the 0-50 isn't a big concern), and it puts you several clicks closer your greater distance zeroes.

I put this firmly into the "user preference" category.

[Failure2Stop]

Are you shooting 3 inch targets or human sized targets? I thought you said human in first post.

If you are shooting human sized targets, why hold over from 0-25? Put the dot in his chest, and at most you are 2.8 low using your optic.

I guess it is not the zero distance I am confused about, but why you think you need to hold over vs a human at close ranges under standard battle conditions (sniper etc, I can see need for more precise targetting).

This is about effectively dealing with human threats, not "human sized targets". The size of the vital areas selected for destruction are much smaller.
To reliably instantly shut down a human threat, your target area in the head is a roughly 3" circle in the center of the head. Sometimes parts of the head can be obscured by hard cover or things I don't want to put bullets into.

Common loop-holes in walls (murder holes) can be as small as 3" and still permit the bad-guy to aim through them while shooting. Putting bullets through them and not around them end the fight a lot faster.

The precision requirement of a "W" in a gunfight is greater than most people understand.

[RichDC2]

Thank You for your time and sharing your knowledge!

[Renegade]

This is about effectively dealing with human threats, not "human sized targets". The size of the vital areas selected for destruction are much smaller.
To reliably instantly shut down a human threat, your target area in the head is a roughly 3" circle in the center of the head. Sometimes parts of the head can be obscured by hard cover or things I don't want to put bullets into.

Common loop-holes in walls (murder holes) can be as small as 3" and still permit the bad-guy to aim through them while shooting. Putting bullets through them and not around them end the fight a lot faster.

The precision requirement of a "W" in a gunfight is greater than most people understand.

Gotcha.

Despite decades of practice, I have never been able to consistently make 3 inch head shots out to 300 meters on a moving target. Thus I aim more for chest core, which I miss more often than not anyway unless really close.

[Failure2Stop]

Gotcha.

Despite decades of practice, I have never been able to consistently make 3 inch head shots out to 300 meters on a moving target. Thus I aim more for chest core, which I miss more often than not anyway unless really close.

Yeah, those 1 MOA moving targets hits are rough :p

For anything past 200 meters, unless I have a lot of time, I am happy with good upper torso hits from a "fighting" AR with an optic that supports perfomance down to 3 meters. Change those variables to "precision rifle" and higher magnification optics and expected performance changes.

Glad we got on the same page.

[Ironman8]

I personally use a 100 meter base zero on everything.
That being said, for long range applications I maintain recorded data out to as far as I can shoot, in 100 meter increments (or even better in 50 meter increments past 600 yards), so I can dial to a true zero and then apply wind hold.

If shooting at unknown distances it is common to dial to a specific range and then employ mil-holds for stuff at closer range.

Further, if shooting for precision at long range, the mil-holds for sub-200 are pretty easy (and the 0-50 isn't a big concern), and it puts you several clicks closer your greater distance zeroes.

I put this firmly into the "user preference" category.

Thanks for the input.

Now I see that "side" of it. However, I'll probably just stick to a 100m zero like you said...

[nickdrak]

Outstanding! I will be sure to refer to this if my department ever decides to get on the ball with our rifle policy.

[KrampusArms]

Thank you for taking the time to make this thread. This has been book marked. Appreciated!

[polydeuces]

I tried it - it works!!!!
You should see my misses at 400M now.....:D

[Renegade]

Glad we got on the same page.

Thanks for answering my questions.

[Submariner]

The precision requirement of a "W" in a gunfight is greater than most people understand.

Would you please explain this? No lo comprendo.

[Failure2Stop]

Would you please explain this? No lo comprendo.

Sorry, "W" as in "win".
This is why I generally avoid sports references :)

Sent from my DROID RAZR using Tapatalk 2

[Beat Trash]

I'm an inter-city LEO using a 16.1" Colt 6920 as my Patrol Rifle. Most of my potential engagement distances are well within 50 yds. But some school hall ways can get almost to the 100 yd range, not to mention large parking lots of business, grocery stores, Wal Marts, ect.

I've been using the 50/200 yd zero since we instituted the Patrol Rifle program, but lately have been giving more thought to the 100 yd zero.

The more I thought about it, the more I felt it had merit for my needs.
Thanks for posting this F2S. You managed to explain it in such a way that even I can understand. You've sold me on the concept.

[WARPIG [USMC]]

Great write up! I'll be using this technique on Saturday when I sight in my RDS.

[evotistic]

This is a great explanation. Thank you for taking the time to post this! I have always used the 25M zero (only way I've been trained in the service). I wish line units would take the time to consider the merits of the 100M zero.

[hotrodder636]

Great explanation dude, thanks for taking the time to explain and show details.

[Kodiak]

F2S, when I first got my AR I didn't know which zero to use. I went out to the indoor range and zeroed it to 25 yards. I read your article on your site and was impressed with the explanation. My first trip to a 100 yard range, I zeroed it to 100 yards. It has worked well in the tactical matches I've been shooting too.

[JJM]

My apologies if this has been addressed elsewhere, but for your POA with a red-dot, do you prefer to use the center of the dot as your reference point, or do you use the top edge of the dot for greater precision? I suspect that it's less of an issue with the 2 MOA dot, but I'm just curious.

Thanks for the great summary.

[Failure2Stop]

My apologies if this has been addressed elsewhere, but for your POA with a red-dot, do you prefer to use the center of the dot as your reference point, or do you use the top edge of the dot for greater precision? I suspect that it's less of an issue with the 2 MOA dot, but I'm just curious.

Thanks for the great summary.

I use the center of the dot as the apparent size of the dot will change with varying intensity, illumination, and background color.

[3 AE]

Will you make this thread a Sticky or add it to the AR15 Zeros and Trajectories Sticky?

[lifebreath]

100 m zero guy here for the reasons stated. However, I initially used it because I got an ACOG, and it was calibrated for a 100 m zero.

Regarding irons, I like the Revised Improved Battlesight Zero, but you need the A2-style drum rear sight to implement it. This scheme provides the ability to use the small aperture with an approximate 100 yard zero, the large aperture in the standard 50/200 range, and the small aperture again from 300 yards out using the drum.

[Preliator]

F2S, great explanation on how it works. I did the ground work for the 100m zero on our 25m indoor range and did a quick field test on it out at an LE 3 gun match last Saturday. The 25m ground work put me dead on (pure luck I think) and I was able to shoot fairly competatively, at least in the rifle portion. I am going to be working to get all of our folks swapped over to the 100m zero on thier rifles, in this line of business it just makes to much sense.

+1 on making this a sticky.

[sholling]

Thank you very much this is great information!

[SMETNA]

You sold me. I'm all for less guesswork, less variables, less math.

Thanks for taking the time.

[MistWolf]

Well written and the graphics clearly illustrate the point. This is typical of why I pay attention to what F2S posts

[bullittmcqueen]

Excellent info here. This is exactly the type of information I was interested in when i broached this topic last week....thankfully a member here sent me your link. Great work!

[SMETNA]

For those running with an EOTech, I found this quick range estimation diagram. Basically, if your target is standing inside your 65moa ring, your range is roughly 100m.

http://img516.imageshack.us/img516/3236/eotrchrangefindingpx8.jpg

[ra2bach]

For those running with an EOTech, I found this quick range estimation diagram. Basically, if your target is standing inside your 65moa ring, your range is roughly 100m.


don't you mean yards?

[xcravx]

Just wanted to say thanks for taking the time to make this thread F2S. In-depth explanations like this are truly appreciated.

[exiledtoIA]

Will do. Printed, laminated and in the "Big Black Book of Guns and Stuff".



You are more than welcome to use it, just throw M4Carbine.net and F2S a kind word while you do :D.

[MrSmitty]

Recently converted from the 50/200m zero to the 100m zero after reading this article. The images using a red dot on a torso sized target are excellent.

I've been able to reach out a little further with my 10.5"/T-1 combo more intuitively now.

Jack, thanks again for doing this write up and answering my questions in the other thread a few months back!

[gun71530]

Great information. I have been using the 50/200m zero, but i will be switching after reading this.

[StrikerFired]

I have been using the 50/200 as well. After reading this I believe that I am going to give the 100 meter zero a try.

[Wiggity]

Someone please sticky this thread

[SMC527]

Great info!

Just as a compare and contrast, could you post the same pictures and diagrams with the 50/200 zero also. It would help me visualize the difference

If it's not too much trouble

[Moltke]

Great info!

Just as a compare and contrast, could you post the same pictures and diagrams with the 50/200 zero also. It would help me visualize the difference

If it's not too much trouble

Seems like that might get confusing. There is another thread on the 50/200 zero.

[Gunzilla]

Jack, awesome write-up, thanks for taking the time to compile and post this data.

A couple of questions about zeroing: What do you think of zeroing 1 round at a time with a 1 minute pause between rounds fired?

The last few times out to zero my ARs I've loaded only 1 round into the magazine, fired and left the bolt open, loaded another round into the mag and fired again after about a 1 minute pause. I repeated this until I have shot 3-5 rounds before making adjustments. Do you see any negatives to zeroing in this manner? (I shoot a free floated hand guard on both my ARs, if that helps you to answer the questions)

It does seem that when I do this my groups are tighter because the barrel does not heat up too much between rounds as it would by loading 5 at a time and firing them at a faster pace....thus I think it helps with shooting a more consistent group. Or am I just imagining things?

I usually end my zeroing session by loading 5 rounds at a time and shooting three 5 round groups to check my results....and so far I've been pleased with the overall results.

Your input, or input from others, would be appreciated.

[a0cake]

A couple of questions about zeroing: What do you think of zeroing 1 round at a time with a 1 minute pause between rounds fired?

The last few times out to zero my ARs I've loaded only 1 round into the magazine, fired and left the bolt open, loaded another round into the mag and fired again after about a 1 minute pause. I repeated this until I have shot 3-5 rounds before making adjustments. Do you see any negatives to zeroing in this manner? (I shoot a free floated hand guard on both my ARs, if that helps you to answer the questions)
.

Zero procedure is REALLY shooter dependent. Some guys who aren't so consistent do need to put 3-5 rounds on target so that a center-point can be established and adjusted from. If there's 4-5 MOA between shots and you try to adjust off of 1 or 2 rounds you're going to end up chasing ghosts on paper and getting nowhere fast.

Others are able to do "one round adjust," because they're consistent shooters who are able to call their shots and make adjustments off of single rounds - saving time and ammunition. So it really varies based on experience. Of course final zero confirmation should be multiple rounds.

As for your other question of loading one round and waiting a minute between shots - whatever works for you, but this is generally inadvisable.

You're likely changing position, taking your cheek off the stock, and in general doing a lot to interfere with grip, cheek-weld, body position, pretty much everything that breeds consistency and translates to tight groups. IMO you're far better off loading up a 28 round magazine so that the gun balances as it would during normal carry (don't underestimate the effects of balance and pivot point on POI). Instead of waiting a long time between shots, fire rounds at a moderate and comfortable cadence, focusing on consistent body position, sight alignment, and point of aim between rounds (and don't forget to breathe!). I think you'll learn to see better results this way, and your zero process will look a whole lot more like regular shooting - which is always a good thing.

[a0cake]

Jack, good job getting this all down on paper and consolidated. As you know I'm also a firm believer in the 100M zero, so this will be a good resource for guiding people this direction in the future. Thanks.

[bp7178]

I think if you're breaking your stock/cheek weld and reloading the rifle every shot, you are potentially introducing inconsistency.

As a counter point, I doubt you would notice tighter groups due to barrel heat, but probably because you have less eye strain and you are breaking your focus and allowing your eyes to relax between shots while loading.

I see everyone (almost) in this thread referring to everything in meters. I haven't been to a LE or civilian gun range ever that is run out in meters.

I think its worth noting that yards and meters aren't the same thing, as we all know, and the farther out you go the bigger the difference gets. We think and write everything in MOA, how many fractions of an inch per click etc. I think a lot of people write/speak meters without making the distinction.

I really like 10 round groups to confirm zero with, depending on the ammunition. If you are shooting match ammo, and its a very consistent 1 MOA rifle/ammo combo, you can get away with less than 10. If you are using a 2-4 MOA rifle with 2-4 MOA ammo, your 10 round groups will largely be very consistent, albeit on the large side, which is fine.

I see guys at the range shoot a good 5 round group out of many, then quietly chalk the bad up to shooter error and get frustrated. When in reality, the groups aren't consistent due to shooter error, but due to lack a statistical significance with low count groups.

Its that consistency in group size that allows you to accurately know the center of your group and adjust accordingly. That is the one thing I've noticed when I went to ten round groups, all of the sudden I'm MUCH more consistent.

The take away, CONFIRM your zero with a 10 shot group at a minimum.

[Littlelebowski]

Needs to be stickied.

[SMETNA]

Yeah, this thread needs some of that hot sticky stuff

[bwhamilton]

this is amazing jack, thanks!

[SMC527]

Seems like that might get confusing. There is another thread on the 50/200 zero.

It could certainly go in another thread.

It was just very easy to visualize POI with those diagrams, so I was requesting a set for 50/200 from the OP.

[Raven Armament]

So optic zeroed at 100 and irons 2 in high at 100? I'm a little confused when the irons are discussed. With a 100 zero, I assumed it was both optic and irons at that zero.

[Failure2Stop]

So optic zeroed at 100 and irons 2 in high at 100? I'm a little confused when the irons are discussed. With a 100 zero, I assumed it was both optic and irons at that zero.

You can go that way, and out to 100 it works just as well, but the trajectory past 150 starts to get well enough behind and below the FSP to make it difficult to achieve consistent good hits on anything but large stationary targets.

It isn't an issue with the zero, it's simply the nature of the beast with irons. Optics generally do not have the issues with target obscuration and non-target focus, which makes them easier to apply offsets.

If you do not have a need to shoot past 125 meters, I would not argue with having both sighting systems on the same (100 m) zero. I like to shoot out to 300 whenever I can, and zeroing irons 2 to 3 inches high at 100 lets me do that without needing to adjust my irons.

I'm thinking about throwing another article together discussing the irons and the method to my madness. One of the reasons that I haven't is that Paul Howe already wrote about his method (3" high at 100) a few years ago (check CSATs website or do a search here and it should pop up), and like most things that Paul Howe writes it is concise, simple, and well illustrated. It was reading his article that pushed me to reevaluate what I was doing with irons.

Another reason to do a 2-3" high at 100 meters is that it works well with an IBZ setup rear sight, so you retain the range capability of the A2 style rear sight or other range/drop compensating rear sights like the KAC and Matech.

Sent from my DROID RAZR using Tapatalk 2

[Rodgerk]

Indeed a great article. Jack - is this any different from the long standing practice of many of us big game hunters to sight their 30 caliber class hunting rifles in to shoot around two inches high at a hundred yards and thereby be reasonably assured of hitting a vital zone out to around 250 yards and the bullet staying inside a "tunnel" of around 5" from the muzzel to the target? I have sighted my '06, 270's, and 308 in to hit at "2 high at a hundred" and have been in good shape out to a range beyond which an ethical hunter rarely takes a shot, generally speaking.

I just acquired an M4 and immediately sighted in at 2" high at a hundred and it occurred to me that it would take care of business as far as my eyes could make out a 5" strike zone in any event.

[crh]

zeroing irons 2 to 3 inches high at 100

What's your method for aiming with irons at a 6-8" black target at 100 yards? Do you place the top of the front post right in the center of the target? I'm finding that a bit difficult to do, but probably just need more practice. A 6 o'clock hold (dotting the i) is a bit easier, but then that makes things confusing as you change ranges.

[greatnw]

You can go that way, and out to 100 it works just as well, but the trajectory past 150 starts to get well enough behind and below the FSP to make it difficult to achieve consistent good hits on anything but large stationary targets.

It isn't an issue with the zero, it's simply the nature of the beast with irons. Optics generally do not have the issues with target obscuration and non-target focus, which makes them easier to apply offsets.

If you do not have a need to shoot past 125 meters, I would not argue with having both sighting systems on the same (100 m) zero. I like to shoot out to 300 whenever I can, and zeroing irons 2 to 3 inches high at 100 lets me do that without needing to adjust my irons.

I'm thinking about throwing another article together discussing the irons and the method to my mattresses. One of the reasons that I haven't is that Paul Howe already wrote about his method (3" high at 100) a few years ago (check CSATs website or do a search here and it should pop up), and like most things that Paul Howe writes it is concise, simple, and well illustrated. It was reading his article that pushed me to reevaluate what I was doing with irons.

Another reason to do a 2-3" high at 100 meters is that it works well with an IBZ setup rear sight, so you retain the range capability of the A2 style rear sight or other range/drop compensating rear sights like the KAC and Matech.

Sent from my DROID RAZR using Tapatalk 2

First off thanks for the great write up and the heads up on where to find more explanation on the irons sights side of it. The only question I still have is in regards to CQB(inside the home) distances with the 2-3" high at 100 zero for an iron sighted gun. It seems under 25 yards your hold over would be 4-6"+ or am I missing something? If this is correct, using my gun for primaraly HD but still wanting to be able to hit out to 200 without playing with the sights would you recommend the 50-200 zero vs the 100? Thanks for the help.

[Raven Armament]

If you do not have a need to shoot past 125 meters, I would not argue with having both sighting systems on the same (100 m) zero. I like to shoot out to 300 whenever I can, and zeroing irons 2 to 3 inches high at 100 lets me do that without needing to adjust my irons.
Currently I'm an iron sight shooter. The load I use is a 55gr FMJ @ 2790fps from a 16 inch. Zeroed at 100y I've got a 3" drop at 200y, 7.5" drop at 250y, and 14.5" drop at 300y. Taking shots that long is basically coyote and crows on the farm where ~300y is the longest possible shot. I hold over a bit at 250 and 300. Looking to get an optic for the longer shots and keep the irons in place.

[DacoRoman]

First off thanks for the great write up and the heads up on where to find more explanation on the irons sights side of it. The only question I still have is in regards to CQB(inside the home) distances with the 2-3" hold over at 100 for an iron sighted gun. It seems under 25 yards your hold over would be 4-6"+ or am I missing something? If this is correct, using my gun for primaraly HD but still wanting to be able to hit out to 200 without playing with the sights would you recommend the 50-200 zero vs the 100? Thanks for the help.

It is not a 2-3" holdover at 100yards. The POA is 2-3" below the POI, which is 2-3" above where you are aiming. IOW you will be hitting 2-3" above your POA. It is essentially a bullseye type of zero, where you are aiming at the 6 o'clock of a 6" bullseye, with the bullseye resting on top of your front sight, and hitting dead center, 2-3" above, your POA.

[Rodgerk]

crh - On a B8 target i will try to stay in the center of the target. Granted a six 'oclock hold is easier to consistently pull off but with the M4 the object is to put the round into the black at various ranges when not shooting a blacked out target.

[kcmo83]

The only question I still have is in regards to CQB(inside the home) distances with the 2-3" hold over at 100 for an iron sighted gun. It seems under 25 yards your hold over would be 4-6"+ or am I missing something?

Expanding on what Vlad said...

You still won't be off more than the distance between the top of your front sight and the bore-axis with the irons zeroed that way. The closer you get to the target (from 25), it would be physically impossible for you to be "4-6"+" off, as you say, because there simply isn't enough elevation in the sights to make a difference. Check out the graphs in this thread (https://www.m4carbine.net/showthread.php?t=65679) to give you a better idea. You'll notice that none of the zeros, whether 25, 50 or 100 yards cause the round to ever go 'lower' than the distance between the front sight post and bore-axis before ~25 yards.

Bottom line: Zeroing irons as FTS suggests won't make a difference for your CQB hold-offs.

[greatnw]

It is not a 2-3" holdover at 100yards. The POA is 2-3" below the POI, which is 2-3" above where you are aiming. IOW you will be hitting 2-3" above your POA. It is essentially a bullseye type of zero, where you are aiming at the 6 o'clock of a 6" bullseye, with the bullseye resting on top of your front sight, and hitting dead center, 2-3" above, your POA.

Thanks for the correction, I meant zero not hold, I edited in the correction. I understand how the 3" high at 100 zero works(I think ;)) just am curious how it performs under 25yds.

[greatnw]

Expanding on what Vlad said...

You still won't be off more than the distance between the top of your front sight and the bore-axis with the irons zeroed that way. The closer you get to the target (from 25), it would be physically impossible for you to be "4-6"+" off, as you say, because there simply isn't enough elevation in the sights to make a difference. Check out the graphs in this thread (https://www.m4carbine.net/showthread.php?t=65679) to give you a better idea. You'll notice that none of the zeros, whether 25, 50 or 100 yards cause the round to ever go 'lower' than the distance between the front sight post and bore-axis before ~25 yards.

Bottom line: Zeroing irons as FTS suggests won't make a difference for your CQB hold-offs.

Not sure how I missed that thread. Thanks for the info, answers my question completely.

[Ironman8]

crh - On a B8 target i will try to stay in the center of the target. Granted a six 'oclock hold is easier to consistently pull off but with the M4 the object is to put the round into the black at various ranges when not shooting a blacked out target.

If you are going to zero with irons, you will get a much better group (zero) when holding at a definitive point on the target. On a B-8 target, you have 5.5" of black circle to aim at. If aiming for center, how do you know that you're aiming dead center? Or an inch high? Or an inch low? See what I mean?

If you hold at the 6:00 edge of the target, now you have a much more definitive aiming point to work with in order to get your zero...whether you want your zero at POA or 2-3" above POA.

Once you have the zero, and are shooting the target for competition, practice, ect. then, as with anything else, just remember your holds.

[Rodgerk]

Ironman8 - you are of course exactly right and I do use a six 'oclock hold if I want to shoot for goups, eg., when building up loads. My point of reference for that answer is the objective of putting several rounds into a chest cavity sized group out to two hundrd yards. If I always held at six wouldn't that tend to put the group low at that distance from POA? Would you still advise holding a six picture and be comfortable that the group would be POA=POI to do the job in SD mode?

Beyond 200 I hope to get my hands on my Model 70 308. Know exactly how that old friend groups out to 400.

[crh]

If you are going to zero with irons, you will get a much better group (zero) when holding at a definitive point on the target.

That makes sense, and that's what I'm doing now, but once my range changes, what do I do? If I zero for a 6 o'clock hold at 100yds, hitting my groups in the bull, then move down to 50yds... do I still go for 6:00, then hold slightly high? 25yds, same thing?

[Ironman8]

Ironman8 - you are of course exactly right and I do use a six 'oclock hold if I want to shoot for goups, eg., when building up loads. My point of reference for that answer is the objective of putting several rounds into a chest cavity sized group out to two hundrd yards. If I always held at six wouldn't that tend to put the group low at that distance from POA? Would you still advise holding a six picture and be comfortable that the group would be POA=POI to do the job in SD mode?

Beyond 200 I hope to get my hands on my Model 70 308. Know exactly how that old friend groups out to 400.

Where you hold on your target will depend on where you zeroed the sight system in relation to the bullet strike (and of course what the distance is to your target)....see the rest of my comments below...



That makes sense, and that's what I'm doing now, but once my range changes, what do I do? If I zero for a 6 o'clock hold at 100yds, hitting my groups in the bull, then move down to 50yds... do I still go for 6:00, then hold slightly high? 25yds, same thing?

This is where you will need to know your holds. The below Green Bolded portion is the answer as to what your holds would be with a 2-3" POI above your POA @ 100m.

The Red Bolded portion is the reason that F2S doesn't zero at 200 m for this trajectory...

The Black Bolded portion is the reason that F2S even does this in the first place.

Now you may think, oh well he really has a 200m zero then...well no, since he didn't zero at 200m. He zeroed for 2-3" above POA @ 100m. There is a distinction there. He just knows his holds and that's why it works for him.

(F2S, if I'm off somewhere here, please come in and correct)



Iron Sights.
When it comes to irons I prefer to zero 2 inches high at 100 meters. This is primarily to maintain awareness of the target at distances that would otherwise obscure the target with the front sight. Since iron sights require the shooter to focus on the front sight for accurate placement of shots, it is difficult to see what to shoot at as distance increases. The trajectory is very similar to the 50/200 zeroing scheme, but a 50 yard/meter zero still leaves a large margin for possible error in adjustment; zeroing at 200 is extremely time-consuming unless the target can provide rapid feedback without requiring the shooter to cover 200 meters to check his groups, and wind begins to make a distinct effect on the bullet at 200, which can cause a lot of issues with deviation adjustment.

Execution.
Zeroing at 100 meters (regardless of POI in relation to POA) removes a lot of "slop" in adjustments, virtually all sight adjustments are referenced at 100 yards/meters (which makes adjustments easier), wind only slightly effects the POI, and it gives the shooter time to hone fundamentals at a distance relevant to the prone position.

Me personally, I like to zero with the top edge of the front sight being POA=POI.

But I will still hold at the 6:00 edge of the target during the zeroing process. The only difference between my groups and say F2S's (at the same POA) is that my group will have a "group zero" on the 6:00 edge, while F2S's group will be zeroed 2-3" above mine.

On longer range targets where the front sight will obscure the target, I personally will come up on my POA from the 6:00 direction so that it is less of a guess as to where my POA actually is.

Hope that clears it for you guys...

[Redhat]

On longer range targets where the front sight will obscure the target, I personally will come up on my POA from the 6:00 direction so that it is less of a guess as to where my POA actually is.

Ever try the side aiming technique with irons?

[Failure2Stop]

Thanks for the correction, I meant zero not hold, I edited in the correction. I understand how the 3" high at 100 zero works(I think ;)) just am curious how it performs under 25yds.

It's ok, but not quite as gentle of a rise as the 100 meter POA/POI zero.
It shoots about the same as the IBZ, 50, and 200 zeroes.

[Failure2Stop]

Me personally, I like to zero with the top edge of the front sight being POA=POI.


And that's prefectly fine for the majority of realistic tasks with irons inside 200 meters in the real world.



But I will still hold at the 6:00 edge of the target during the zeroing process.

I greatly prefer to hold center of the zeroing target rather than try to define where the "edge" of the blurry target is. The center of the black blur will always be the center of the bull. The edges are harder to define, and even worse when trying to establish a linear distance. If you focus on a distant bull and then pull your focus back to your front sight you will see that the apparent size of the blur changes from when you are focusing on the bull. Where is the edge that you are holding? Is it the begining of the grey outline around the blur? The start of the black in the blur? The middle of the two? What is the linear difference between the three possible "edges"? Also, as you look over the front sight you will see distortion of the blur where it "touches" the front sight, which makes defining the edge even dicier as it relates to distance.

The fact that one can decide to place the front sight on an easily referenced part of the outside of the blur and adjust sights to hit specific part of the target is not really the same as establishing an offset POI in exact relation to the POA. The method works for bullseye shooting as one doesn't care about the hard numbers as far as offset goes, all that matters is that the holes are in the middle of the target.



On longer range targets where the front sight will obscure the target, I personally will come up on my POA from the 6:00 direction so that it is less of a guess as to where my POA actually is.


This is a method that can work, as does bringing the sights onto target from the side, but it only really works well with stationary targets. Human threats have a habit of moving around, hiding, and generally avoiding being shot. Losing observation of the threat in order to place the shot greatly reduces the probability of being successful with the shot and of assessing effect though the sights.

Seeing how the discussion is developing I have decided to put together another article and illustration array to more concisely and effectively convey the concept.

[feedramp]

Thank you for this excellent post, F2S!

Question about ammo variation: How much difference in POI will one typically see out to 200m using the 100m zero with .223 vs 5.56? Say PMC Bronze .223 vs XM193 vs M855.

Does one need to re-zero for each type of ammo or can one get a solid 100m zero using some cheap .223 and still be pretty close POI for the majority of the distance out to 200 if they throw a few XM193 or M855 down range?

Assume the higher pressure 5.56 will have a flatter arc over that distance than .223 would?

[Beat Trash]

Thank you for this excellent post, F2S!

Question about ammo variation: How much difference in POI will one typically see out to 200m using the 100m zero with .223 vs 5.56? Say PMC Bronze .223 vs XM193 vs M855.

Does one need to re-zero for each type of ammo or can one get a solid 100m zero using some cheap .223 and still be pretty close POI for the majority of the distance out to 200 if they throw a few XM193 or M855 down range?

Assume the higher pressure 5.56 will have a flatter arc over that distance than .223 would?

It really depends on your definition of "pretty close". For me, there is enough difference in the PIO vs. POA when going from M855 to M193 to want to adjust the sights. The difference in the velocity of the various 55 gr bullets, from some of the slower Russian 223 to 5.56mm M193 will cause enough change in the POI to warrant my changing the settings.

I personally don't switch around with my ammunition. I pick a training round and stay with it. I also keep notes on each gun. So if I need to switch, I can tell how many clicks it took to the last time, and be real close in case I can't verify the setting.

[davidjinks]

My experience with ammo differences...

I learned the 100 yard zero at EVTC taught by F2S.

I zeroed my rifle at 100 with MK262 MOD1 ammunition. Through the class I used up the last of that ammo. My fall back ammo was Hornady TAP 75 gr. 223 (Smoke tracers rock!).

On our confirmation zero (Right before our quals) I had to adjust 1 click right from my original zero with the MK262.

Now, compare that to the IMI M193 and the PPU M193, I had to adjust ~3 clicks right for windage and 1 up for elevation. This was all at 100 yards.

When we went out to 300 I didn't really have any issues. I was still banging steel with very little correction on my offsets. That was with a 4 MOA T1. That was using MK262, 75 gr. 223 TAP, PPU M193 and IMI M193.

At the range I go to at home I can shoot 100 yards regularly.

With my MK12 and NF 2.5-10x24 scope I can definitely tell a difference with ammunition.

My zero is with MK262.

IMI M193 has a 1.5 MOA correction right and .25 MOA correction up.
PPU M193 has a 1.75 MOA correction right and .25 MOA correction up.
BH 77 gr. .223 has a .25 MOA correction right
BH 75 gr. .223 has a .25 MOA correction right and .25 MOA correction up.
LC M855 has a 1 MOA correction right and .50 correction up.

I have a bunch more in my book but that's the ammo I use most every time I go to the range.



Thank you for this excellent post, F2S!

Question about ammo variation: How much difference in POI will one typically see out to 200m using the 100m zero with .223 vs 5.56? Say PMC Bronze .223 vs XM193 vs M855.

Does one need to re-zero for each type of ammo or can one get a solid 100m zero using some cheap .223 and still be pretty close POI for the majority of the distance out to 200 if they throw a few XM193 or M855 down range?

Assume the higher pressure 5.56 will have a flatter arc over that distance than .223 would?

[Cameron]

Fantastic post. It should be stickied.

Cameron

[Failure2Stop]

Question about ammo variation: How much difference in POI will one typically see out to 200m using the 100m zero with .223 vs 5.56? Say PMC Bronze .223 vs XM193 vs M855.

Does one need to re-zero for each type of ammo or can one get a solid 100m zero using some cheap .223 and still be pretty close POI for the majority of the distance out to 200 if they throw a few XM193 or M855 down range?

Assume the higher pressure 5.56 will have a flatter arc over that distance than .223 would?

David showed his data points, which are similar to my experience, which is to say: they are all different, and the only way to really know is to do a comparison shoot. Some are close enough to be interchangable at 300 meters, some similar ammo will be significantly off at 100 meters.
Generally, I have found that I can stay within 2 MOA from my zero load with my high density ammo. Then again, I have also seen shifts in excess of 5" when switching from M855 to Mk262, so my preference and recommendation is to check zero when using different ammo before putting confidence into it.

The velocity difference and trajectory path between 5.56 and .223 out to 300 meters is transparent. I personally prefer to shoot 5.56, but thats for a few reasons, of which velocity IS a factor, but not the "the" factor.

I prefer to zero with my "high performance" ammo and do sub-100 meter work with cheap bulk ammo.

[ROUTEMICHIGAN]

I need to add my thanks. Bravo Zulu, F2S.

[Evil Bert]

I use the same method when i zero by using this target. It is setup to be placed at 25m and if done properly, it will yield you a true 100m zero and all the benefits that come with it.

[Failure2Stop]

I use the same method when i zero by using this target. It is setup to be placed at 25m and if done properly, it will yield you a true 100m zero and all the benefits that come with it.

I only accept a 25 meter zero (1.5" low) if a 100 meter range is not accessible. I have never seen a 25 yard/meter expedient zero require no change at 100 yards or greater.
If 25 is all you got, do what you can, but don't think that it's the same.

I also have no use for dedicated short range zeroing targets. I just move POI to 1.5 inches low on whatever I can aim at easily and move back to 100 for the real zeroing as quickly as possible.

[swedeboy]

Thanks for the info

[doubletap2211]

F2S, just wanted to say thanks for this post. Excellent resource for a great zero.

[Steve]

Very well done sir

[Kodiak]

Question: You stated to shoot 1.5" low at 25 yards. From the center of my red dot to the center of my bore I measured 2.75". Should I be shooting 2.75" low at 25 yards or still shoot 1.5" low?

Thanks and great read!

[SMETNA]

Question: You stated to shoot 1.5" low at 25 yards. From the center of my red dot to the center of my bore I measured 2.75". Should I be shooting 2.75" low at 25 yards or still shoot 1.5" low?

Thanks and great read!

Your POI should be 1.5" lower than your POA at that distance, regardless of your optics' height over bore.



What I think he was saying is that in general, shots landing within a 3" circle is pretty reasonable for combat accuracy. So if you zero at 100m, and if you aim 1.5" high at anywhere between 25m and 200m, your shots will always hit inside that 3" circle. This does not take into account the inaccuracy of the ammo or the weapon. If everything else is gtg, 25m - 200m should involve zero guesswork using this method.

[BangBang77]

This may sound like a dumb question, but for the 100 meter/yard zero, what do I set my rear elevation knob at during the zero process?

The only zero process I am familiar with is the 25 meter zero that I learned at Ft. Benning back in the 90s, where you set the knob at the Z marked position for the M4.

I have a LE6920 flattop, using a LMT rear sight instead of the carry handle and Troy Alpha freefloat. 16" bbl, standard front site base.

I've read this entire thread multiple times along with Molon's thread on zeros and trajectories and I haven't found a definitive answer. Both of these threads have a plethora of outstanding information. Thanks for all the hard work each of you have put in.

[Failure2Stop]

This may sound like a dumb question, but for the 100 meter/yard zero, what do I set my rear elevation knob at during the zero process?

The only zero process I am familiar with is the 25 meter zero that I learned at Ft. Benning back in the 90s, where you set the knob at the Z marked position for the M4.

I have a LE6920 flattop, using a LMT rear sight instead of the carry handle and Troy Alpha freefloat. 16" bbl, standard front site base.

I've read this entire thread multiple times along with Molon's thread on zeros and trajectories and I haven't found a definitive answer. Both of these threads have a plethora of outstanding information. Thanks for all the hard work each of you have put in.

I personally prefer to use a variation of the 100 meter zero that is similar to a 50 or 200 meter zero, and for that setup (2 inches high at 100 meters) the rear sight is set to 6/3 -4 (will require resetting the rear elevation drum as per the IBZ if you want to retain the ability to dial for distance).
You can simply spin the elevation drum to 3 (6/3 no gap) if it has not been set to allow negative travel below 3. That's essentially all you are doing when you reset the rear drum anyway, except that you can set it correctly to account for trajectory at long range.

[BangBang77]

I personally prefer to use a variation of the 100 meter zero that is similar to a 50 or 200 meter zero, and for that setup (2 inches high at 100 meters) the rear sight is set to 6/3 -4 (will require resetting the rear elevation drum as per the IBZ if you want to retain the ability to dial for distance).
You can simply spin the elevation drum to 3 (6/3 no gap) if it has not been set to allow negative travel below 3. That's essentially all you are doing when you reset the rear drum anyway, except that you can set it correctly to account for trajectory at long range.

Roger that, F2S. Much appreciated.

My department rifles are zeroed with the 25/300 meter zero. My sheriff and most of my fellow deputies are former .mil so we are all more familiar with it. We've actually been discussing going with a different zero and I think this is the answer we've been looking for.

We're a small rural department of only 8 full time deputies with limited fund so do you mind if I use your charts for reference only (no printing) to get my boys squared away?

[Failure2Stop]

Roger that, F2S. Much appreciated.

My department rifles are zeroed with the 25/300 meter zero. My sheriff and most of my fellow deputies are former .mil so we are all more familiar with it. We've actually been discussing going with a different zero and I think this is the answer we've been looking for.

We're a small rural department of only 8 full time deputies with limited fund so do you mind if I use your charts for reference only (no printing) to get my boys squared away?

No problem, feel free to PM or email if you need more detail.

[rob_s]

Roger that, F2S. Much appreciated.

My department rifles are zeroed with the 25/300 meter zero. My sheriff and most of my fellow deputies are former .mil so we are all more familiar with it. We've actually been discussing going with a different zero and I think this is the answer we've been looking for.

We're a small rural department of only 8 full time deputies with limited fund so do you mind if I use your charts for reference only (no printing) to get my boys squared away?

I'm curious, you say 25/300... Do you all actually shoot at 300, or any other distance besides 25, to confirm? I ask because a lot of departments seem to use the 25 simply because it's what they have available at the range.

Departments aren't the only ones though. I've maintained for a long time that the only reason most people use the 50/200 is because they can't shoot to 100. Not because they don't have the range available, but because they cant put enough of a group together at 100 to adjust POI. ignoring the fact that what they have at 50 is an initial intersection and if they are lucky a theoretical zero at 200, or somewhere thereabouts.

[BangBang77]

I'm curious, you say 25/300... Do you all actually shoot at 300, or any other distance besides 25, to confirm? I ask because a lot of departments seem to use the 25 simply because it's what they have available at the range.

Rob, no we do not have access to a 300 meter range, but we do confirm at 100. We verify the we are approximately POA + 6.0" at a 100 meters and we call it good. Each of us has a homemade laminated range card taped to our buttstocks with the holdovers for the 25/300 POA/POI differences for the various distances, but by doing it that way we introduce added variables into making a shot at distance that could be eliminated with the 100 yard zero.

[rob_s]

Rob, no we do not have access to a 300 meter range, but we do confirm at 100. We verify the we are approximately POA + 6.0" at a 100 meters and we call it good. Each of us has a homemade laminated range card taped to our buttstocks with the holdovers for the 25/300 POA/POI differences for the various distances, but by doing it that way we introduce added variables into making a shot at distance that could be eliminated with the 100 yard zero.

Thanks for the reply. At least you're ahead of most then. Out of curiosity, if range cards are used, is range estimation taught? Being in construction, around people who measure and survey things every day, I see how few people are actually capable of correctly estimating the distance between two points, and it only gets worse when one of the points is you!

If you have 100 available I'd certainly prefer to use the 100 yard zero myself.

[orionz06]

100m/100y, it just ****ing works. Stop the mind ****ing and shoot the damned gun.

Excellent write up.

[BangBang77]

Thanks for the reply. At least you're ahead of most then. Out of curiosity, if range cards are used, is range estimation taught? Being in construction, around people who measure and survey things every day, I see how few people are actually capable of correctly estimating the distance between two points, and it only gets worse when one of the points is you!

If you have 100 available I'd certainly prefer to use the 100 yard zero myself.

Yes, sir, we do regular range estimation that we confirm with a laser range finder, and we have a former National Guard sniper in the department that helps out with this.

Again, yes the 100 yard zero will eliminate all the holdover shit we currently do until we move past 200 yards. We have a 100 yard range in our county to get this done.

Thanks.

[BangBang77]

No problem, feel free to PM or email if you need more detail.

Roger that, will do. Again, thanks for putting all this info together and making it easy to comprehend.

[BangBang77]

100m/100y, it just ****ing works. Stop the mind ****ing and shoot the damned gun.

Excellent write up.

Outstanding contribution to this thread, sir. Thank you.:)

[Kodiak]

...Not because they don't have the range available, but because they cant put enough of a group together at 100 to adjust POI...
Have you been reading my mail???? :sarcastic: I don't do very well at 100 yards BUT I do try! My red dot with a 3 MOA dot doesn't help either. Ever since I read this thread, I started zeroing at 100 yards. I've started shooting local tactical matches and this zero has helped, except when I forgot about the offset when going thru the shoot house and was hitting low. :D Great read and thx for putting out all this info for everyone to learn from.

[Submariner]

I'm thinking about throwing another article together discussing the irons and the method to my madness. One of the reasons that I haven't is that Paul Howe already wrote about his method (3" high at 100) a few years ago (check CSATs website or do a search here and it should pop up), and like most things that Paul Howe writes it is concise, simple, and well illustrated. It was reading his article that pushed me to reevaluate what I was doing with irons.

Paul Howe: The Battlefield Zero (http://www.combatshootingandtactics.com/published/thebattlefieldzerofullpictures.pdf)

[DJ_Skinny]

Thank you F2S. I was an inexperienced shooter that thought the 50yd IBZ was the shit. Now that you've set me on the straight and narrow, I see the errors of my ways. Consider me another convert, and thank you again for the info posted here!

[bullittmcqueen]

Thanks again F2S for this excellent post. I just wanted to ask if it's ok to paraphrase some of the information for a blog post I am doing, with acknowledgements to F2S right up front of course.

Thanks again Jack.

[wake.joe]

Travis Haley makes a good case for a 300 yard Zero.

http://www.youtube.com/watch?v=8iCNIRuQuBg

[Littlelebowski]

Travis Haley makes a good case for a 300 yard Zero.

http://www.youtube.com/watch?v=8iCNIRuQuBg

Can you argue his points against F2S?

[Kodiak]

Actually, he didn't make a case for any zero. He stated for a person to pick the zero that best meets their needs. When talking about zero, not everyone had access to beyond 100 yards and/or have vision issues at distance.

Sent from my DROIDX

[Littlelebowski]

Cool, I hate watching videos and was wondering if that was a drive by post.

[orionz06]

I am curious how the 300m, as shown, works out with an 11.5" and a 16". I know I can get hits out to 350 with both my 11.5" and any of my 16's with the same zero. I will have to take a look into the charts to see if that is also the case with what he has shown in the video. Not sure if it will be enough for me to change, I would rather shoot than figure out a new zero.

[wake.joe]

Well, first of all, I did not see anyone mention it in the thread and thought it would be relevant to the conversation.

The video does a great job of "Summing up" each of the different zero ranges.


Cool, I hate watching videos and was wondering if that was a drive by post.

I may have phrased my statement incorrectly, and I apologize if so. I did not say, and certainly did not imply, that a 300 yard Zero was the best. Nor did I say that Travis says the 300 yard zero is the best.

I only said that he made a good case for it.

I only meant to imply that, based on his video, the 300 yard zero looks to be the best compromise. 5 inches of deviation from 0-300 yards is a very small window.

I, personally, can accept 5 inches. If you or your situation can not, than Zero differently.
I am in no way trying to discredit F2S information, technique or this thread.

[orionz06]

Is that the zero you use?

I would also question the abilities of most shooters when shooting out at 300m with a red dot and middle of the road ammo shot out of a chrome lined barrel.

[wake.joe]

Is that the zero you use?

I would also question the abilities of most shooters when shooting out at 300m with a red dot and middle of the road ammo shot out of a chrome lined barrel.

Not sure if you're asking me, but;
No. I zero at 100 yards with my reddot equipped rifle.
But only because I have no use for it to shoot further than 100 anyway. If forced to go the distance, the holdhover is simple. I can and do make hits at 300 with this rifle on steel. I could not give you a group size.

On my TR24 equipped rifle, however, I do use a 300 yard zero. For two reasons- Number one, the reticle does not lend itself to using hold overs. Number two, that rifle does see a lot of use at varied distances (Vs sub-100 distances) and if I ever really needed to make a super "Precision" shot at some of those ranges, the reticle is much more suited to hold-under.

[Failure2Stop]

Thanks again F2S for this excellent post. I just wanted to ask if it's ok to paraphrase some of the information for a blog post I am doing, with acknowledgements to F2S right up front of course.

Thanks again Jack.

Go right on ahead.

[Failure2Stop]

Well, first of all, I did not see anyone mention it in the thread and thought it would be relevant to the conversation.

The video does a great job of "Summing up" each of the different zero ranges.


You are free to post whatever you want, wherever you want, however, there are several threads out there, one of which I directly link to in the initial post, that discuss the different zeroes and their trajectories, and how people suppose that one may be better in one regard to another.

This thread is my summation of the advantages that I have noted and the reasoning that I use to support my strong preference for a 100 meter zero after using quite a few different ones in every application between range plinking and combat. I really don't care who prefers what, or who uses a 100 meter zero, or if anyone else even cares. This was originally posted on my website, and I decided to put it here so I wouldn't have to refer people off-site, and the response from members was great enough to get it stickied. Use what you want when you want where you want, I'm not saying that anyone is wrong or that anyone should do it this way, but I implore that people make a decision based on what they do with their guns and not what other people do with their guns, and get out and actually shoot.

[wake.joe]

It wasn't meant to say "Well -this- guy does xxx!!!"

I just (incorrectly) thought it would be relevant. Talking about hold overs, I thought some input about not having any hold overs to your 300 yard mark would be interesting.

Sorry to shit in your thread.

[Failure2Stop]

It wasn't meant to say "Well -this- guy does xxx!!!"

I just (incorrectly) thought it would be relevant. Talking about hold overs, I thought some input about not having any hold overs to your 300 yard mark would be interesting.

Sorry to shit in your thread.

Sorry if I came across that way, not my intent. Sometimes my desire to be concise and direct can come across as terse.

Your comment of "I use a 100 yard zero for xxx, and a 300 yard zero with my TR24, due to reticle design for xxx" are certainly pertinent.

There ain't no perfect solution for everything, and that perspective might be helpful for someone with similar application of a similar optic.

I was simply noting that the thread was not intended as a cumulative list of different zeroes and their applications, but rather a focused one on a specific envelope of use.

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[Arctic1]

@F2S:

What group size do you find acceptable in terms of adjusting POI?

[eesmith4]

Good thread.

I've used the 100 meter zero before and liked it, but ended up transitioning to the 50/200 because I found 5.56 trajectories with that zero more closely matched easily identifiable 300-400-500 yard holdover points with my nightforce's FC-2 reticle. I went ahead and started using the 50/200 with the other AR's as well, to maintain consistency.

Much hay is made WRT different zeros, however I believe the zero itself isn't as important as knowing and properly applying the holdover/unders for your particular chosen zero. I would agree that the 100 meter zero is probably the simplest and easiest for a RDS equipped carbine.

Much as mission drives the gear, in my case optics(or more specifically, reticle) drove the zero. As always, YMMV.

[bullittmcqueen]

I wanted to post two things in follow-up here:

1. First, I experienced first hand last weekend the benefit of the 100 yd zero, over what I had been previously using, the 50/~200. The 3-gun match I shot in had a max range of 100 yards on some 6 inch steel gongs. Naturally, since I was zeroed for 100, this was no problem. Some of the other guys I observed having some serious problems with hold offs. I was fortunate enough to win that stage overall even though I was using a non-magnified Aimpoint M2, over a lot of shooters using variable low-power optics.

2. If you use the 100 yard zero, you can very easily calculate hold offs for any distance using the Knights Bullet-Flight app for iphone and driods. I was already using this app for dope on scoped rifles, and it works just as easily if you create a new ballistic diagram for your optic. I created one for an Aimpoint which tells me inches of crop for any distance. Just thought I would pass it on. It's been very helpful to me when shooting past 100 yards with the M2.

http://itunes.apple.com/us/app/bulletflight/id300903039?mt=8

[kenndapp]

has any one had the chance to play with this zero past 100 yards with typical hunting/tac/duty style ammunition?

things like mk318,75grotm's, 62and70 gr tsx's, 64gr soft points, 62gr sp?? i have a strong 100yard zero with ssa 64gr ppt but really have no idea whats its doing past 100 yards as i have no access to ranges past 100 yards. sad, i know.

just wondering how "off" the results become when switching bullet weights and styles. and of course with different weigh comes different velocity, bc's, ext....

http://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi6.jpg http://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi7.jpg
http://i296.photobucket.com/albums/mm174/Fail2Stop/poapoi8.jpg


f2s, i know there is no way to give any sort of definitive answer on what an unknown load will do at distance without physically doing it.

but can we say......most bullet weights and styles coming out of 14.5-16" barrels will have similar results??

[SouthGA]

Thanks to all that have supported this thread.
It has been an excellent resource to me.

[Failure2Stop]

has any one had the chance to play with this zero past 100 yards with typical hunting/tac/duty style ammunition?

things like mk318,75grotm's, 62and70 gr tsx's, 64gr soft points, 62gr sp?? i have a strong 100yard zero with ssa 64gr ppt but really have no idea whats its doing past 100 yards as i have no access to ranges past 100 yards. sad, i know.

just wondering how "off" the results become when switching bullet weights and styles. and of course with different weigh comes different velocity, bc's, ext....

-images snipped-

f2s, i know there is no way to give any sort of definitive answer on what an unknown load will do at distance without physically doing it.

but can we say......most bullet weights and styles coming out of 14.5-16" barrels will have similar results??

These are general guidelines, based on 16" barrels launching 62 grain bullets.
My classes shoot out to at least 275 yards, preferably out to 300 meters, on BCC or smaller sized targets. Some of the shooters use barrels as short as 8.5", and while their holds are more drastic than the average, they are more similar to the guideline than not. Still, to be good at it, you need to do it.

Remember that there will always be some degree of offset during zeroing, and that slight deviation will be more apparent at long range.


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[ClearedHot]

If you are running a Matech BUIS which does not have a 100m setting, how would you go about zeroing it at 100?

[Failure2Stop]

If you are running a Matech BUIS which does not have a 100m setting, how would you go about zeroing it at 100?

You could just set it at "200", and do the front sight adjustment necessary to bring it to POA/POI at 100. However, given the utility of that sight, I would either go for a zero that allowed me to maintain distance adjustments as marked or go to an alternate design.

Another however:
I prefer my irons to have a 50 or 200 meter zero (depending on what distance I have available). I like the amount of target that can be seen over the sight at mid-range, though this introduces different rules on holds with one sighting system. I zero at 100 meters, but with POI between 2 and 3 inches above POA, and then confirm drop at range on steel.

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[GunBugBit]

Nicely presented and laid out, thank you.

[buckpatriot]

For my first reply as a new member, I must say I enjoyed and appreciate the well explained 100M zero concept and application. As one of the biggest users of small arms in the world, the US Army does a VERY poor job of teaching arms skills to the masses, unless part of specialized training. They have really missed the boat on the little things that could have saved many lives in combat. Fortunately, with the conflicts that we have been involved in, in the 11+ years, they have become somewhat less risk adverse than in the past allowing Soldiers to actually train in CQB with live ammo, etc. Hopefully, they ramp it up more.

I am case in point with this article. My most recent deployment, I received the latest Army training. Have been in for a long, long time and am competent in weaponry but was not over whelmed with the training but did appreciate the most aggressive cqb I have received since I have been in.

Long story short, it wasn't until I got to Afghanistan and our 5 man team, one of which was a weapons instructor, scheduled weekly and extensive range time. This is where I learned to really become confident, accurate and effective with my M4. Coincidentally, it is also why I recently bought my first one . We zeroed our weapons at about 25 yds, as the FOB range did not allow more. When doing our cqb, stress shoots, etc at <25 yds- I noticed that my shots were always low by a couple inches so I had to consciously put my CCO red dot a couple inches above the desired target. I got very good at doing it, but had we own this info, it could make all the difference in the world in critical situation. I look forward to getting out to the range armed with this new info. Thanks and sorry for the long winded post!

[LMT Shooter]

I feel a little retarded when I read some of this stuff. why, when we can see that a 50/200m zero keeps our rounds within 2" POA/POI out ot well over 200m, do more shooters not use the 50/200m zero? Am I really missing something important here?

[nml]

Odds are your 50m zero and your 200m zero are two different zeroes. Just something to keep in mind.

[Ironman8]

I feel a little retarded when I read some of this stuff. why, when we can see that a 50/200m zero keeps our rounds within 2" POA/POI out ot well over 200m, do more shooters not use the 50/200m zero? Am I really missing something important here?

Here's one (or a few) reasons why...

http://www.kyledefoor.com/2010/12/12-days-of-zero.html

[DieselCowboy]

Why mess with hold unders AND hold overs for the 50/kinda200-dependent-on-ammo when you can learn one simple set of hold overs and still keep poi/poa on a 3" circle out to 200M with the 100M zero? That second zero with 50/200 isn't 200M on the nuts, so you're throwing in the variable of your skill at range estimation to pick an over or under.

On a human sized target using the 100M zero, if a 2MOA dot doesn't cover the whole head assume a POA/POI of nuts to -3", if the dot matches the head size assume 200-250M and aim at the neck for center mass hits, if your dot obscures the head then cover the head and get a center mass hit. If your dot obscures most of or the whole body, you have more variables than just drop over distance to worry about. No guessing where that second zero is and if you'll hit high or low, you'll always have POI under POA and never over.

But I kill paper pictures, they never hide or use cover.

[nml]

Kyle makes some great points as usual. We're very blessed to have guys like him, Larry, Jason and others around.

[LMT Shooter]

Odds are your 50m zero and your 200m zero are two different zeroes. Just something to keep in mind.

You are correct & I am aware of this, I was oversimplifying my question. I was referring to either a 50m or a 200m zero, which are close to each other, but not the same thing. I apologize for making myself look less well informed than I already am. I joined here to learn & appreciate your clarification.

[LMT Shooter]

Here's one (or a few) reasons why...

http://www.kyledefoor.com/2010/12/12-days-of-zero.html

I have read this a few times. Some pretty convincing stuff there, thanks for the heads-up. I might be learning something here, I'm not sure, but it doesn't hurt too bad.

[Ironman8]

I have read this a few times. Some pretty convincing stuff there, thanks for the heads-up. I might be learning something here, I'm not sure, but it doesn't hurt too bad.

No prob. That's what we're all here for.

Aside from what was written in the article, I do remember that Kyle has said in the past that with a 200m zero, under stress and in battlefield conditions, it is easier to shoot over your target due to not remembering your hold-under.

[LMT Shooter]

Yeah, his blog said that was an issue. The biggest thing I took away from it was what he said about the size of likely targets. I had always thought of a target as being a whole person, but the reality of it may only be a head, or part thereof, which makes a 2" or 3" difference POA/POI into a huge difference, and I had not thought of it that way. Honestly I must admit that I am still not 100% convinced to go with a 100yd zero, but I am certainly re-evaluating it's merits, after I had written it off. I am inclined to think that to reap the benefits of the 100yd zero requires more skill than I have now, so first thing I need to do is become a better shooter & a lot better at range estimating.

[T2C]

You could just set it at "200", and do the front sight adjustment necessary to bring it to POA/POI at 100. However, given the utility of that sight, I would either go for a zero that allowed me to maintain distance adjustments as marked or go to an alternate design.

Another however:
I prefer my irons to have a 50 or 200 meter zero (depending on what distance I have available). I like the amount of target that can be seen over the sight at mid-range, though this introduces different rules on holds with one sighting system. I zero at 100 meters, but with POI between 2 and 3 inches above POA, and then confirm drop at range on steel.

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I zero a carbine the same way. I set my sights to hit 2" high at 100 meters. For head shots at 40 meters to 150 meters you hold on the tip of the nose, the ear lobe or the base of the skull where it meets the back of the neck. For a head shot inside a small to medium size building, you hold in the center of the forehead, the top of the ear or the occipital bun.

[pingdork]

I've been using the 50/200 simply due to the ease of being able to see my zero target better at closer range when using an aimpoint. My 5-shot groups at 50 with RDS are right around 2". Bad or good IDK, but best my eyes can do. What would be an acceptable group at 100m? I like your explanation of the ease of use of the 100m zero, just not sure if I can make it work for me.

FWIW using anACOG on my other rifle, I had no issues getting good 1.5" groups at 100m. Little bit of magnification goes a long way.

[Failure2Stop]

I've been using the 50/200 simply due to the ease of being able to see my zero target better at closer range when using an aimpoint. My 5-shot groups at 50 with RDS are right around 2". Bad or good IDK, but best my eyes can do. What would be an acceptable group at 100m? I like your explanation of the ease of use of the 100m zero, just not sure if I can make it work for me.

FWIW using anACOG on my other rifle, I had no issues getting good 1.5" groups at 100m. Little bit of magnification goes a long way.

3-4" groups at 100 are normal with RDS optics and affordable bulk ammo. I prefer to zero with good stuff (defensive or precision ammo) and check that zero against the POI of the blaster grade ammo. Deviation is usually fine inside 100m.

Big thing is using a target that helps you hold a consistent POA. I tend to use B8 refaces for a lot of stuff, but some folks do better with very bold crosshair type targets. As it is, one doesn't need to be shooting sub 1" groups to have a zero; as long as you can shoot a consistent group you will get the benefit. When using B8 refaces (actually the F2S target) my goal is to have at least 80% in the "10 ring" (~3") during the zero confirmation. Better ammo generally makes that easier.

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[pingdork]

Ok. Will try tomorrow. Hoping I can achieve 3-4" groups so I'll have some idea how much to adjust. Thanks

[T2C]

I find it easier to sight in using a 6 o'clock hold or sub 6 o'clock hold using a ball target. It gets me on paper and where F2S mentioned he wants his carbine to hit at 100M.

Download a SR-1 target and print off a few. Sight your rifle to hit the X ring or lower part of the 10 ring at 100 meters when holding at 6 o'clock on the target.

[CGSteve]

You could just set it at "200", and do the front sight adjustment necessary to bring it to POA/POI at 100. However, given the utility of that sight, I would either go for a zero that allowed me to maintain distance adjustments as marked or go to an alternate design.

Another however:
I prefer my irons to have a 50 or 200 meter zero (depending on what distance I have available). I like the amount of target that can be seen over the sight at mid-range, though this introduces different rules on holds with one sighting system. I zero at 100 meters, but with POI between 2 and 3 inches above POA, and then confirm drop at range on steel.
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Forgive me, but you have me a bit confused. Do you have a 50/200 zero on your BUIS, or do you also zero your BUIS at 100 (but for it to impact high)?

My concern is similar to the poster who mentioned the Matech sight not having a 100 meter setting. In fact, I'm not familiar with any BUIS with one. The LE agency I work for, we are issued the Matech BUIS (we have little to no allowance for customization) and are required to zero at 100 yards/meters. I have my personal rifle set up to be 95% like my work rifle but I have the ability to play around with more distance on a desert range on my own time and want to see the results.

Are the settings on the Matech then rendered "useless" if you don't follow its instructions (by zeroing at 100 on the 200 for example)?

[Failure2Stop]

Forgive me, but you have me a bit confused. Do you have a 50/200 zero on your BUIS, or do you also zero your BUIS at 100 (but for it to impact high)?

My concern is similar to the poster who mentioned the Matech sight not having a 100 meter setting. In fact, I'm not familiar with any BUIS with one. The LE agency I work for, we are issued the Matech BUIS (we have little to no allowance for customization) and are required to zero at 100 yards/meters. I have my personal rifle set up to be 95% like my work rifle but I have the ability to play around with more distance on a desert range on my own time and want to see the results.

Are the settings on the Matech then rendered "useless" if you don't follow its instructions (by zeroing at 100 on the 200 for example)?

It is a 2-3" high POI at 100.
It is basically the same concept as zeroing slightly low at 25 to get a zero similar to a 50/100/200/300/whatever zero.

Zeroing 2-3" high at 100 with your rear sight set on 2 will be very close to a 200 zero, but if you actually need to accurately shoot at long range I would recommend confirming your long range zeros at actual distance.

This is, of course, regarding iron sights. I greatly prefer POA/POI at 100 with optics.

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[SMT85]

just moved to this zero from the 50 meter zero, thank you for the write up and detail of your post. i am pretty happy with the 100 meter zero, cant see my self switching to anything else.

just took some experimenting with different targets to see what i was aiming at with a 2moa dot, lol

[dogz]

I agree! I just went to the 100 yd zero about a month ago and I am still learning the holds at different ranges. Graet info in this thread. I just want to say Thank you!!

[Glockman1968]

https://www.m4carbine.net/showthread.php?p=1627501#post1627501


A picture is worth a thousand words, by Paul Howe.

[chungdae]

If you zero'd with 223 and then tried to zero with 556 how off would the POI be with 223?

[wahoo95]

If you zero'd with 223 and then tried to zero with 556 how off would the POI be with 223?

Depends.....you'd have to shoot it and see. When you zero with a particular ammo your zero is for that particular ammo. Changing ammo or even changing lots of nother same ammo can affect your zero. Even changes in weather conditions can affect it slightly. This is why its always nice to double check your zero when you have time. All these changes can be small, however I feel its good to know since the changes typically require some sorta adjustment to optics.

[Jimbaran]

This is awesome. Thank you for posting!

[Tzed250]

Bump.

Confirmed my 100yd zero yesterday, then had great fun with reactive steel from 25 to 100yds. It works.

[sboers]

A question:

My rifle has a 100M zero with both the iron sights and my Aimpoint. My iron sights are the LMT BUIS, and they are set up via the RIBZ method (6/3 sight, -6 clicks of travel = 100M setting). I zeroed the irons as per the OP, with the point of impact being approx. 2" high (4" circle, lolipop the target, rounds impact at the center).

How much is this going to change the trajectory at longer ranges?

[T2C]

A question:

My rifle has a 100M zero with both the iron sights and my Aimpoint. My iron sights are the LMT BUIS, and they are set up via the RIBZ method (6/3 sight, -6 clicks of travel = 100M setting). I zeroed the irons as per the OP, with the point of impact being approx. 2" high (4" circle, lolipop the target, rounds impact at the center).

How much is this going to change the trajectory at longer ranges?

With a carbine you would be zeroed for 200 meters and can shoot neck hold on a silhouette at 300 yards.

[sboers]

With a carbine you would be zeroed for 200 meters and can shoot neck hold on a silhouette at 300 yards.

Excellent, thanks.

I have shot steel plates out to 400M with the irons, and simply used the adjustments. Holding COM, I hit the plate. However, the sight lives on the 100M setting 95% of the time, so I was curious what it was doing on paper.

As for the neck hold @ 300M, I assume that doing so places my shot in the chest?

[T2C]

Excellent, thanks.

I have shot steel plates out to 400M with the irons, and simply used the adjustments. Holding COM, I hit the plate. However, the sight lives on the 100M setting 95% of the time, so I was curious what it was doing on paper.

As for the neck hold @ 300M, I assume that doing so places my shot in the chest?

It would be a high chest shot with M193 and center chest shot with M855 shot out of a carbine.

[ManchuMedic]

thanks for the info

[Straight Shooter]

Are there any videos..youtube or otherwise...that show a visual explanation and example of what the op and others have explained here? Especially the RIBZ method?

[Failure2Stop]

Are there any videos..youtube or otherwise...that show a visual explanation and example of what the op and others have explained here? Especially the RIBZ method?

Ribz is a zeroing scheme for folks that are tied to the A2 style rear sight.

A 100 meter/yard zero is more oriented to optics.

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[Straight Shooter]

deleted.

[britishtq]

I use a 50 yard zero but I'll have to check this out.

[T2C]

Ribz is a zeroing scheme for folks that are tied to the A2 style rear sight.

A 100 meter/yard zero is more oriented to optics.

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Now that I am experimenting with optics I find a 200 meter/yard zero works best with iron sights and a 100 meter/yard zero works best with magnified optics.

[Ledanek]

Advance apology to the Admin/ moderator is this is the appropriate place to this query.

I'm limited to going to two range for BCM Midlength: Article 2 (25 yard range) (http://www.article2range.com/gun-range/) or GAT ( 50 and 75 yard range) (https://www.gatguns.com/pistol-rifle-gun-ranges/rifle-range)
Article 2 is my choice due mainly to proximity. This is where I started sighting my middy (iron sights only). My experience is mainly on what I learned in the Marine Corp.
Article 2 is also where I co-witness my Aimpoint H1.
I'm okay with this setup since, I'm not into long range shooting. Mostly for home protection/SHTF. That's a separate thread.

In between getting invited to GAT, where a few friends took me to the 75 yard, of course my shots where wildly off. Already I knew, I cannot use my H1 in this range.
So for 40 rounds, I had to walk my shots to bulleyes. Two shots and adjusting my frontsight, mostly going down, using GAT's rifle sled (which I'm not familiar, but, got the jest of keeping my shots steady.

Maybe due to excitement, I forgot that I may have ruined my zero for my intended purpose of owning this rifle.

So I asked to be educated on where is a better place to zero rifle again: Article 2 or GAT. --- intended purpose again is for home defense/SHTF

I'm not against, seeking professional schooling since both offer classes or even getting a 3x multiplier scope to compliment my Aimpoint H1

THANKS in advance

[Soularcher]

Most excellent thread, glad I found it. Can't wait to get out and give it a try. Sadly, we presently have about 6 inches of snow and counting... :( Thank you for sharing!

[TACTICAL45]

Great read, thanks for your time and effort putting this together. I am sure many shooters out there can benefit from this. Myself, I have dedicated systems. I never touch the adjustments on the 5.56, I just hold from 50 to 400. The .308, I hold to a specific distance, then use my dope for farther distance to get me on target.

[cpoth]

Jack, thank you very much for the write up and thread. By the way, I have heard great things about the Volusia matches since moving back to PA, I have to say it was a pleasure to shoot with you and learn from you when I lived/competed down there.

As per the 100m zero, I gave this a try for a few weeks on one of my rifles and have since switched my other rifles and gathered data on my rifles out to 300 yards (my home range is measured in yards). Below is an example of pictures of data I like to keep on my rifle stocks that helps me remember where each is hitting at various ranges. Its fairly rough and will change as I incorporate more shooting and data points.

This is from a 16" Noveske middy with a Trijicon TR24 Red triangle with M193 ammo.

The drops are measured in inches and are unique to my rifle/optic/eyes. The red dot on the image is where I would hold my triangle in this case and the "X" would be POI.

Not that it is the greatest chart/picture but if anyone would like me to email a word document of the miniature IDPA targets please just send me a PM and I'd be happy to do so.

EDIT: This picture is about 1.5" x 3/4"

Take care,
Chris

[JBall]

Thanks for taking the time to put this together, it is very informative.