View Full Version : Zeroing my DD & Learning BUIS part II. (Pics)
ComeAndTakeIt
04-30-11, 20:22
So, in a previous thread (http://www.m4carbine.net/showthread.php?t=79954) I was given some good advice, including using the small aperture when shooting at 50 yards or greater! :blink: LOL Somehow I forgot to my first time out.
Anyway, much better results today!
This pic shows two targets (50 yards). One with Large aperture and one with the small... I bet you can guess which is which. :cool:
I also moved it to a 6 o'clock hold.
http://img716.imageshack.us/img716/6929/photo1ay.jpg (http://img716.imageshack.us/i/photo1ay.jpg/)
Interestingly, I shot a lot worse with the large aperture than I did the other day. I think it's because I was using a different sight picture the first time. When I can see the 'goal posts' of the front site because of the large aperture, I tend to put those in the middle and the actual center post down lower. I noticed fixed it with the later shots in the pic above. So the early shots were quite low and the later were closer.
The range didn't allow 25 yard shooting to try the larger aperture at a closer range for when I'd actually use it. They only allow .22 and pistols on the 25 yard range. How stupid is that? Why would I shoot my pistol 25 yards hardly ever in real life? It should at least be open to both rifle and pistol, but if they had to choose just one, rifle should win in my book!
I have an indoor nearby that will allow me to shoot there at close range, but I have to buy frangible ammo. $$$
I'll do that another day because the range charges $35/box for frangible. I need to order some now I guess.
I also found that smaller targets (another suggestion in the previous thread) helped too...
No, the holes in the white paper aren't mine. I used a previously hung target for my shoot-n-c target. (Saving that money for frangible ammo!) :sarcastic:
http://img703.imageshack.us/img703/9669/photo2ir.jpg (http://img703.imageshack.us/i/photo2ir.jpg/)
This is a smaller target where I used the large aperture...
http://img222.imageshack.us/img222/1301/photo5af.jpg (http://img222.imageshack.us/i/photo5af.jpg/)
So, all in all, a much better day!
Lots of fun. I went through about 300 rounds. No issues with my DD so far.
(only side note... it was frickin' windy! I don't think it moved the bullet in flight much at 50 yards, but it sure moved me while trying to hold the rifle still!)
Thanks again for the tips. I'm going to try and continue to master the BUIS, but I have to admit, I'm really tempted by an Aimpoint M3. I'm fighting the urge because I know when I get one, I'll stop using the BUIS and I really want to master them first.
Good shootin'! Saw your other thread, and I'm glad you got to go out and put that advice into practice. Good tips that I'll use for the next range trip too.
I was at ASC before noon and yes it was windy as hell!! I took out my K.I.S.S. rifle to get sighted in. I have the elevation down but need to come back and dial in the windage. I couldn't hold steady enough. The past few weekends I've gone out have been super windy.
You did better than I did.
ForTehNguyen
04-30-11, 21:12
Nice I go to this range too. 50 yard zero is better for the AR anyways
You might want to fine tune that zero at 200yds when you have the time. 50yd and 200yd zeros are close, but I have found, depending on the ammo, there could be a difference. I use a 5" shoot n c at 200yds. A 4 moa dot will center nicely. If I have to adjust at 200, it usually doesn't make much difference at 50. With a 50, 200 zero you should be about 1.5 high at a 100, and about 8" low at 300.
Technically there's no such thing as a "50 yard zero" as it would be better termed a "50 yard initial intersection" as zero is really the second point of intersection not the first. With the 100 yard zero you're damn close to both initial and second intersection so the terminology is more interchangeable. Achieving a true zero at some distance is the preferred method. 200 yards gives you the most flexibility out to distance, but I prefer the 100 yard as it gives me the best results for my actual use. Either is fine and is more a matter of personal preference, making a choice, and understanding the mechanics of what you've done and how to hold based on same at various distances.
Either way, my suggestion is to fine-tune a true zero at the second intersection and then work backwards to check and closer range.
Facilities, obviously, can present challenges in this.
Nice, heading to pick up my DD tomorrow. Won't be able to shooti it though, too many chores to do. I am going to sight it in when I get back from work, can't wait and nice shooting!! PS....are you using the DD A 1.5 sight for your BUIS?? I plan on using it and when I get around to adding an RDS, I am just going to leave it on and co witness at the 1/3 position.
If you are using the DD rear sigh you need to realize that it uses an A2 aperture, and understand that the holes are not in the same plane, and what that means for your groups and you zeroing.
When I wanted to spend some real time with the irons I sought out a co-planer fixed rear iron sight and the only one I could find was the Troy, so that's what I used.
If you are using the DD rear sigh you need to realize that it uses an A2 aperture, and understand that the holes are not in the same plane, and what that means for your groups and you zeroing.
When I wanted to spend some real time with the irons I sought out a co-planer fixed rear iron sight and the only one I could find was the Troy, so that's what I used.
Ok, I have an MI fixed rear BUIS on my SW and it works nicely. I believe it has an A2 as well. I am using the small aperture when I zero. When you say not in the same plane, do you mean small aperture vs large aperture?? Thanks.
Yes, the centerline of the big hole and the small hole are not the same distance from the centerline of the bore.
Yes, the centerline of the big hole and the small hole are not the same distance from the centerline of the bore.
Ok, understand, so just pick one and use it correct??
I think that's best. I only use the small one. Read this:
http://www.m4carbine.net/showpost.php?p=668454&postcount=2
ComeAndTakeIt
05-01-11, 20:59
That explains why when I went back to the large aperture, my shooting was horrid. Even compared to the first trip out where I only used the large aperture.
I wondered if the center was the same on each aperture, and it's good to know they're not.
what do you mean when you say 6 o clock hold?
ComeAndTakeIt
05-01-11, 21:29
Nice, heading to pick up my DD tomorrow. Won't be able to shooti it though, too many chores to do. I am going to sight it in when I get back from work, can't wait and nice shooting!! PS....are you using the DD A 1.5 sight for your BUIS?? I plan on using it and when I get around to adding an RDS, I am just going to leave it on and co witness at the 1/3 position.
Congrats! You'll love it. I am 100% satisfied with mine. I am using that sight as well and plan to do the same co witness when I get an Aimpoint.
ComeAndTakeIt
05-01-11, 21:31
what do you mean when you say 6 o clock hold?
I put the bullseye of the target on top of my front site post. It looks like a pumpkin sitting on top of a fence post.
Like this... although this isn't representative of an AR site picture, but the same idea...
http://img841.imageshack.us/img841/9373/targetsixoclock.jpg
got it. never knew what this was called.
One slang term for that is called "lollypopping" the target.
Yeah, I like the top of the post cleaving the middle of the bull.
urbankaos04
05-02-11, 03:23
Technically there's no such thing as a "50 yard zero" as it would be better termed a "50 yard initial intersection" as zero is really the second point of intersection not the first. With the 100 yard zero you're damn close to both initial and second intersection so the terminology is more interchangeable. Achieving a true zero at some distance is the preferred method. 200 yards gives you the most flexibility out to distance, but I prefer the 100 yard as it gives me the best results for my actual use. Either is fine and is more a matter of personal preference, making a choice, and understanding the mechanics of what you've done and how to hold based on same at various distances.
Either way, my suggestion is to fine-tune a true zero at the second intersection and then work backwards to check and closer range.
Facilities, obviously, can present challenges in this.
I use a 50 yard "zero" and have used it to good effect all the way out to 305 yards when I had access to a range that had steel targets out that far. I primarily shot XM193 and just used the ballistic chart info for XM193 I received via TOS. I have no complaints with this set-up.
Can you expand as to why the 100 yard zero works best for you? I'm just curious.
Oh, and by the way, I have a TROY BUIS, and that is what I was using when I was shooting out that far.
Just know that this usually turns into more "nuh-huh, you're a dummy, my zero can kick your zero's ass".
In short, this is why I prefer it. There are a whole host of other reasons, but this is the biggest reason for me. It is not an absolute, as I have some guns zeroed at 200, but this is what I prefer on most of my guns.
http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/50vs100.jpg
urbankaos04
05-02-11, 12:28
I agree, Rob, I am not here to get into an verbal internet fisticuffs over the AR15 zero. I just merely wish to relay my experience, and it may be wrong, as I do not have any formal training. I also want to add that I do value you're opinion and have solicited your opinion in the past. And, if I may, I would like to supply a link to a thread over at TOS (yes, I understand that some look down on that site, but there are individuals over there that are able to provide good info) regarding this very topic: http://www.ar15.com/forums/topic.html?b=3&f=18&t=512335.
I've gotten some really good ballistics charts from Molon for XM193, and other loads, for a 16" barrel and it has worked pretty good for me when shooting to 305 yards.
I am going to hopefully have access to a range where one can shoot out to 400+ yards and hope to really fine tune my 200 yard zero and see how it goes out to 400. I dunno, I may end up changing what I'm using.
ETA: Hmm, in reading Molon's post and looking at the 100 yard zero it does seem pretty good if one is shooting within a certain distance and, yep, there is less deviation. Hmm, I utilized the 50 yd "zero" as I decided it was the best compromise some time back due to it allowing one to shoot out further without having to do as much holdover at longer ranges with other zeros. Hmm, I need to rethink some things, now. How do you like that?!... ;)
I didn't think you were looking to start shit, just cautioning you that this often becomes one of those heated topics.
I'll go a bit further, since I'm feeling salty, and say that the reason most people "zero" at 50 is that it's the closest zero they can attain while still appearing to know what they are doing. :sarcastic: If they thought they could get away with a 25 yard zero they'd do it!
Shooting at 100 is harder than shooting at 50. Shooting at 200 (as even the 50 really should be done) is harder than shooting at 100. However, the center of a group is the center of a group whether it's a 1" group or a 6" group. And if one lacks the fundamentals to shoot to the limits of the ammo and gun they are shooting, zeroing at shorter ranges may well just mask their issues. I've seen people SWEAR that they have a good hard zero at 50 yards and then go through a whole magazine trying to hit an 8" plate at 120 yards. This should be mechanically impossible, but there they are, banging away, and there the steel hits, refusing to *ding*. :blink:
No matter what distance you zero, you owe it to yourself to check POI against POA at all distances you have access to, or may be required to engage targets. You'll note that the 100 yard zero hits just at 2" low according to that graph at 200 yards. With what ammo? It's unlikely to be the same with XM193 as it is with BH 77 grain. But few people know this because few get out there and test it in their own guns.
I don't care what zero anyone else uses, but I hear a lot of tall tales told about zeros, especially when we have a longer range stage and I turn my Sordins up so I can hear the chatter behind the line when I'm running shooters. :D
ComeAndTakeIt
05-02-11, 13:53
After doing this 50 yard, I am doing 200 the next chance I get. My range goes out to 500 yards, but the closest you're allowed to target is 50 (25 is and less if .22lr and pistols only! :( ), and it's on 50, 100, 200, 300, 400, 500. Nothing in between.
As I stated in my OP, it was CRAZY windy, so anything over 100 would have been a waste of time IMO. Not sure how it translates to rifle, but it was a 4 club wind if you're playing golf. :)
I'm looking forward to refining this 'zero'. I really need a good spotting scope for 200 yards though. I wish there was a place that rented them.
urbankaos04
05-02-11, 13:59
Paul Howe prefers the 100 yard zero, which can be found here: http://www.combatshootingandtactics.com/published.htm
In skimming through his post, I remember thinking back to the first day I read it and how it seemed to be a lot of work for my lazy ass and just stuck with the 50 yard "zero." :blink: However, I will be going back to give a thorough once over to see what it offers over what I'm currently using. As always, YMMV.
I think the 200 is the better "rifleman's" zero. The issue is that I am not a rifleman, I'm a carbine shooter. Never say never, and all that, but I'm not engaging targets past 200 yards. Most people wouldn't even be able to accurately range to 200 yards. Knowing ranges from a known defensive position is something else entirely.
Having a laser rangefinder leads to some fun games. Ask people "how far away do you think that X is?" and see what they come up with before lasing it. Sometimes they'll be off enough to matter, sometimes they won't.
For me, in the application where I'd use the majority of my carbines given the optics and this shooter, the 100 yard works better as it's less for me to think about. Less overall deviation, the deviation is ALWAYS low, and at the distances I find myself shooting most often the deviation isn't enough to even matter. 2" below POA still rings the 6" plate at 200, or falls where I need it to in the headshot.
CATI
I like the 6 o'clock hold as it's easier for my old eyes to keep a good site picture! :D It's also very useful against "Real Targets" if you know what I mean. ;)
The phenomenon Rob S is describing is known as "point blank zero". It is often used in hunting to determine the proper distance to zero you rifle so that you can aim dead-on out to the maximum distance without adjusting the elevation knobs or holding over. This is the best way to zero your carbine/rifle if you're going to point and shoot.
I never could get zeroed with the A1.5 on my DD and finally put an LMT on there that has windage and elevation. Then, dialed it to the z, zeroed at 25 yards, and put it back on 6/3. The way I understand it is that this will give me poa=poi at 50 and 300 yards. This is my first AR and I'm still learning.
Why are you adjusting elevation at the rear sight? Did you run out of travel in the front?
Why are you adjusting elevation at the rear sight? Did you run out of travel in the front?
Are you talking to me? said in my best Robert Deniro voice.
I'm not sure what you mean by travel in the front.
Are you talking to me? said in my best Robert Deniro voice.
I'm not sure what you mean by travel in the front.
On the AR system you adjust the front sight for elevation and the rear sight for windage.
On the AR system you adjust the front sight for elevation and the rear sight for windage.
I'm not trying to be a butt, but why is there an elevation adjustment on the rear sight then?
http://www.bravocompanyusa.com/v/vspfiles/photos/LMT%20Rear%20Sight%20L8A-2.jpg
Outlander Systems
05-02-11, 22:09
I'm not trying to be a butt, but why is there an elevation adjustment on the rear sight then?
http://www.bravocompanyusa.com/v/vspfiles/photos/LMT%20Rear%20Sight%20L8A-2.jpg
It's used to establish a mechanical zero.
It's not an elevation adjustment, it's more of a ranging adjustment.
I'm staring to think this is one month and one day too late...:blink:
It's used to establish a mechanical zero.
OK, then Rob was talking about raising or lowering the front of the AR to adjust for distances not at 50 or 300 yards. For a minute I thought he was talking about raising or lowering the front sight post. :confused:
OK, then Rob was talking about raising or lowering the front of the AR to adjust for distances not at 50 or 300 yards. For a minute I thought he was talking about raising or lowering the front sight post. :confused:
That is exactly what I'm talking about.
http://www.ar15.com/forums/topic.html?b=3&f=18&t=328143
I'm staring to think this is one month and one day too late...:blink:
LOL! No, I'm just a newbie!
What I posted was how I was taught to zero on a 25 yard range.
LOL! No, I'm just a newbie!
What I posted was how I was taught to zero on a 25 yard range.
OK, now I confess to being really, really lost. Taught by who, and with what gun?
On the AR family of firearms you adjust for windage with the drum on the rear sight, and elevation by turning the front sight post to raise and lower it.
Another resource
http://www.armystudyguide.com/content/army_board_study_guide_topics/m16a2/zero-and-m16a2-rifle.shtml
b. Front sight. To adjust elevation, depress the detent and rotate the sight post (Figure 111). To raise the strike of the round, rotate the sight post in the direction of the arrow marked UP. Reverse the direction of rotation to lower the strike.
If you use the Army zero target (not that I advocate their overall methodology, but the mechanics are what they are), it tells you right on it which direction to turn what knob and how many clicks (at 25 yards).
http://www.armystudyguide.com/content/moxiepix/b1_1524.gif
OK, now I confess to being really, really lost. Taught by who, and with what gun?
On the AR family of firearms you adjust for windage with the drum on the rear sight, and elevation by turning the front sight post to raise and lower it.
I was taught by an instructor at my local range and was using my DDXV carbine. He never said anything about adjusting the front sight post. :angry: Well, that gives me something to think about. Thanks, RobS.
If you use the Army zero target (not that I advocate their overall methodology, but the mechanics are what they are), it tells you right on it which direction to turn what knob and how many clicks (at 25 yards).
rob_s, what target type, bull size, etc. do you use, or recommend, with a red-dot sight (Aimpoint T-1 no magnification) to zero at 100 yards?
If you use the Army zero target (not that I advocate their overall methodology, but the mechanics are what they are), it tells you right on it which direction to turn what knob and how many clicks (at 25 yards).
I could have used this yesterday when I zeroed my sights. The link you provided was an interesting read. I could have used that a few weeks ago when I struggled to zero my sights. One thing that made life easier was spending a few bucks on sight tools.
RogerinTPA
05-05-11, 06:10
After years of competitive shooting using the 6 o'clock hold, I much prefer a POA/POI zero for my carbines.
rob_s, what target type, bull size, etc. do you use, or recommend, with a red-dot sight (Aimpoint T-1 no magnification) to zero at 100 yards?
My favorite zero targets to use are the Shoot-n-C (http://sport.birchwoodcasey.com/Targets/TargetDetails.aspx?ProductID=602d1d99-6a7d-4c4e-ac9d-af041d1fd506) but they get expensive. I designed my own sight-in target in sketchup and then output it to a pdf that I print up. They start with a yellow square, then a gray square, then a black square, then yellow, etc. working from the inside out. I have bold lines on a 1" grid and thin lines between them to make a 1/2" grid. I currently have an 8.5"x11" version but need to make up an 11/17" version for use at longer range with a red dot.
I wonder about the DD A1.5 now that I think about it. Its recommended "zeroing" is a 25/300 with the small aperture and from there to use the large aperture for 0-200 and the small for 300+ (yes there is a 100 yard no mans land with the instructions). Could the large aperture be set for a 100 yard "true zero" in this configuration? I expect it to be some where in this range.
I wonder about the DD A1.5 now that I think about it. Its recommended "zeroing" is a 25/300 with the small aperture and from there to use the large aperture for 0-200 and the small for 300+ (yes there is a 100 yard no mans land with the instructions). Could the large aperture be set for a 100 yard "true zero" in this configuration? I expect it to be some where in this range.
Do we use the 25/300 or 50/200 or 100/300?????
I use 225. That's about 50 with 5.56 and 30 with .308. It yields for me a satisfactory battlesight zero out to 275.
You CHOOSE the zero that matches your intended use and/or ability to use holds to shoot within or beyond its envelope (presuming that that's a concern in the first place).
THEN...you apply it. By shooting.
How does one find out whether a particular zero fits what they have in mind? Find out what different zeros do and where they go. From the same man that explained the RIBZ:http://www.m4carbine.net/showthread.php?t=65679&highlight=zeros
EDIT: Heh, you'll see a lot of the same info repeated in that one with the cited one on AR.15. There's a reason for that...
Also, something that can be a help is to step away from using yards and meters interchangeably. They're not the same, and the ballistic differences get bigger as ranges advance. 100yds = 91.4m, 100m = 109yds. Ergo, presuming one is attempting to apply a 100m zero, and is shooting on a range measured in yards (common on publicly available ranges), the 100yd line is 27' short of your desired distance. Meters vs. yards; pick one and stick with it.
I like the 100 yard zero the best as well because it is the "flattest" out of all within the most effective range of a carbine.
I also use a LaRue BUIS with same plane apertures.
Can anyone tell me why the A2 sights have different plane apertures? I don't get it, what is the logic behind that?
Do we use the 25/300 or 50/200 or 100/300?????
Its the DD recommended zero for the DDM4 running the A1.5 (basically the stock gun, A1.5, 16" barrel, carbine length gas system, and F marked front site post). Says to zero at 25 yards with the small aperture for a 25-300 yard zero but the large aperture is on a different plain and is listed for 0-200 yards which sounds like a zero close to 100 where it doesn't go that much (if any) higher than POA.
I like the 100 yard zero the best as well because it is the "flattest" out of all within the most effective range of a carbine.
I thought 50 yard zero give you flattest range.
I thought 50 yard zero give you flattest range.
There is no such thing as a 50 yard zero.
I was taught by an instructor at my local range and was using my DDXV carbine. He never said anything about adjusting the front sight post. :angry: Well, that gives me something to think about. Thanks, RobS.
Stay away from this so called "instructor".
jackblack73
05-07-11, 16:15
There is no such thing as a 50 yard zero.
I guess it's semantics, but even the chart you posted calls it a 50 yard zero.
Of course mostly ammo dependent if you have a crossing of the first line of sight at 50 yards, your second crossing of LOS will be more correctly around 200 meters or 218-220 or so yards. However with a non magnified optic on a battle rifle on a large plate target or large paper target, one might not really notice a difference. Now if you are going to aim small, miss small and are capable of holding small groups with your rifle / set up, there is a notable difference.
I thought 50 yard zero give you flattest range.
The 50 yard "zero" (as mentioned is the first place POA and POI meet) is flat in that the bullet starts at something like -2.5" at the muzzle and goes up to 0 at 50 and continues to go up to something like +2" (at 100 its like +1.5") and then starts to descend intersecting around 200 yards where its 0 again and continues to go down and hits like -1" at 250. This basically ends up POI 0~250 yards = -2.5"~+2.5" of POA. This is basically 5" of variance to 250.
The 100 yard zero involves it doing something like -2.5 at muzzle and goes up to 0 at 100 but doesn't cross over (or at least not that much) and goes down where at 215-220 its -2.5 again. This zero is something like POI 0~215 yards = -2.5"~0 of POA. This is 2.5" of variance to 215.
Think the 300 yard second intersect zero actually has its first at 30 where the 25 yard intersects again at beyond 400. Either way these go beyond +6" of POA.
So yea, its a "pick your poison" deal. Have it first intersect at 25 for -2.5~+10 to 400, 30s for -2.5~+6 to 300, 50 for -2.5~+2.5 to 250, 100 for -2.5~0 to 200. The 100 yard is really predictable and flat to 215.
Note: These numbers are not exact and just my attempt to sum up and give examples of the basic trends laid down by others although I did attempt to give numbers close to what would be seen. Obviously they can also vary with different sites, ammunition, rifles, etc.
No offense intended, but I think the link from above is much more clear:
"How does one find out whether a particular zero fits what they have in mind? Find out what different zeros do and where they go. From the same man that explained the RIBZ:" http://www.m4carbine.net/showthread.php?t=65679&highlight=zeros
I guess it's semantics, but even the chart you posted calls it a 50 yard zero.
It is not semantics, it is a technicality that matters and simply tossing it out as "semantics" negates certain fundamental principals involved in this process.
It has been my experience that the majority of people that call it a "50 yard zero" and who then utilize same do so only because it is the shortest distance at which they can "zero" given the choices generally presented to them as acceptable, largely because they often lack the fundamentals required to shoot a group from which a center may be discerned.
Not to be argumentative but its either semantics or being a "snob" (granted I agree with the sentiments) or combination of the two.
I see zeros as where POA=POI where you have a first/second intersect of the line of sight, or in the case of a zero where the shot touches but doesn't actually cross the line then one intersect. Then you have the distance at which you sighted it in, which is how far away the target is from the muzzle. Two separate things in my opinion where zero just says where it intersects to give the scheme of the trajectory.
Now if someone has a different opinion like a zero is only achieved when there is only one intersect I would say that is semantics or differing opinions. Saying a zero exists only if the rifle is sighted beyond a certain distance because any less means they just suck adds some snobbery in.
I actually have sighted in a rifle before at 100 yards for about a 50/200 zero by having the POA about 1.5" low of POI. I sighted it in at 100 but that is not its zero which was a little past 50 and I am not sure how close to 200 since I never got that sighting into that much open space and who knows how accurate of a depiction it would be coupled with my skill level. I accepted this because I knew it was likely to yield more precision to what I was going for than actually doing it at 50 which is why I agree with the sentiments of why people should not be sighting in at close ranges but those are still zeros to me although the people might just be failing to actually get it.
Might not agree with this and it might be technically wrong out there some where but its my $.02 and what I separate as zero and sighting in.
To give an answer to an earlier question "Can anyone tell me why the A2 sights have different plane apertures? I don't get it, what is the logic behind that?" The big apertures center is closer to the bore axis than the small aperture which causes the shooter to point the rifle at a shallower angle giving the shot a flatter trajectory for closer ranges where the small aperture gives it a greater ballistic arch and extends where POA=POI out farther for longer ranges. Also large one is much easier to aim through in lower light and small one leads towards more precision but that has nothing to do with being on same plain or not. And yeah, some people find this idiotic and prefer being able to just hold over a target by X amount at Y range and knowing that and to just use the large for quicker acquisitions and lower light and the small for more precise shots.
To give an answer to an earlier question "Can anyone tell me why the A2 sights have different plane apertures? I don't get it, what is the logic behind that?" The big apertures center is closer to the bore axis than the small aperture which causes the shooter to point the rifle at a shallower angle giving the shot a flatter trajectory for closer ranges where the small aperture gives it a greater ballistic arch and extends where POA=POI out farther for longer ranges. Also large one is much easier to aim through in lower light and small one leads towards more precision but that has nothing to do with being on same plain or not. And yeah, some people find this idiotic and prefer being able to just hold over a target by X amount at Y range and knowing that and to just use the large for quicker acquisitions and lower light and the small for more precise shots.
Thanks for the explanation!
In reality, nearly all rifles have two zeros ( I say "nearly" as there may be exceptions I'm unaware of). The first zero is where the bullet crosses the line of sight as it rises up to it. The second zero is where the bullet drops to cross the line of sight again, at a further distance
In reality, nearly all rifles have two zeros ( I say "nearly" as there may be exceptions I'm unaware of). The first zero is where the bullet crosses the line of sight as it rises up to it. The second zero is where the bullet drops to cross the line of sight again, at a further distance
It is not "two zeros". It is an initial intersection, maximum ordinate (furthest distance above line of sight that the projectile travels), and a zero. You do a disservice to the theory of ballistics, trajectories, and marksmanship when you incorrectly state otherwise.
It is possible to have all three occur at the same distance, which is what the 100 yard zero attempts to achieve, and does so pretty closely. The bullet rises, kisses LOS, and decends.
Not to be argumentative but its either semantics or being a "snob" (granted I agree with the sentiments) or combination of the two.
I see zeros as where POA=POI where you have a first/second intersect of the line of sight, or in the case of a zero where the shot touches but doesn't actually cross the line then one intersect. Then you have the distance at which you sighted it in, which is how far away the target is from the muzzle. Two separate things in my opinion where zero just says where it intersects to give the scheme of the trajectory.
Now if someone has a different opinion like a zero is only achieved when there is only one intersect I would say that is semantics or differing opinions. Saying a zero exists only if the rifle is sighted beyond a certain distance because any less means they just suck adds some snobbery in.
I actually have sighted in a rifle before at 100 yards for about a 50/200 zero by having the POA about 1.5" low of POI. I sighted it in at 100 but that is not its zero which was a little past 50 and I am not sure how close to 200 since I never got that sighting into that much open space and who knows how accurate of a depiction it would be coupled with my skill level. I accepted this because I knew it was likely to yield more precision to what I was going for than actually doing it at 50 which is why I agree with the sentiments of why people should not be sighting in at close ranges but those are still zeros to me although the people might just be failing to actually get it.
Might not agree with this and it might be technically wrong out there some where but its my $.02 and what I separate as zero and sighting in.
Everyone is allowed to have their own opinion even when they are wrong. It is only snobbery when someone doesn't understand the concept. Every discipline has it's own jargon. To people that understand the jargon, and the concepts, saying "zero" when you mean "initial intersection" is like saying "clip" when you mean "magazine". You may not like having it pointed out to you, but it doesn't make you right.
and in this case the jargon matters. getting POA/POI at close range is not a complete process.
It is not "two zeros". It is an initial intersection, maximum ordinate (furthest distance above line of sight that the projectile travels), and a zero. You do a disservice to the theory of ballistics, trajectories, and marksmanship when you incorrectly state otherwise.
When the bullet reaches the initial intersection of the line of sight, it's trajectory measured from the LOS is 0 in elevation. When the bullet again intersects the LOS in it's downward path, it's trajectory is once more 0. This has been referred to in several books and articles on the subject as two points of zero- two points at which the trajectory is 0 relative to the LOS in elevation.
It is possible to have all three occur at the same distance, which is what the 100 yard zero attempts to achieve, and does so pretty closely. The bullet rises, kisses LOS, and decends.
You are correct. This had slipped my mind when I posted. If I had taken a moment more to think about it, it would have been obvious what I was missing
Everyone is allowed to have their own opinion even when they are wrong. It is only snobbery when someone doesn't understand the concept. Every discipline has it's own jargon. To people that understand the jargon, and the concepts, saying "zero" when you mean "initial intersection" is like saying "clip" when you mean "magazine". You may not like having it pointed out to you, but it doesn't make you right.
and in this case the jargon matters. getting POA/POI at close range is not a complete process.
So then a zero is only when it touches the LOS but doesn't really cross it? Second intersect? Distance where its sighted in so POA=POI?
I can see saying your gun is sighted in for having x and y intersects as being more correct, but unless a zero is only touching the LOS then why are other distances not correct. Once again I understand how at 25 or 50 yards the shooter doesn't realize how far off their shots will be at distance so its not a good idea to rely on it but what is it suddenly called?
Have to say the clip vs magazine is a bad example, they are pretty much to concretely different things where all I am getting is "a zero doesn't occur until 100+ yards because otherwise its people making up excuses".
Might be wrong but all I see is what a zero is not but not what a zero is which is kind of stupid.
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