18"or16"

[jackinfl]

I am beating my head into a wall over this decision. I want an accurate SPR type upper. I am torn between the 2. I know I will have a small loss of velocity with the 16 as compared to the 18, but will there be any loss of accuracy?

By the way I am also torn between a Centurion Arms Recce and a Larue Stealth 16, on the 16" side.

And a Centurion arms DMR and a Larue Stealth 18, on the 18" side.

I know I am lucky to have these decisions to make.....

Any input would be appreciated.

Jack

[Abraxas]

Out of your choices, whether 16 or 18 I would go LaRue. If you want an SPR I would go with the 18.

[Puffy93]

the accuracy can be great from both sizes at shorter ranges but I think somewhere in the 200-300 yard range the 16" begins to lose accuracy, this is where the 18" excedes. I believe this is because the 16" slows down within a shorter distance

I personaly think that the 18" is a good combination of compactness and accuracy.

This is the impression I was under so someone please correct me if I am wrong

[Iraqgunz]

Something I learned during my 3 Day SPR Sniper Course. Barrel length does not equate to accuracy. Yes, you will have a small loss in velocity. But, if the 16" barrel is quality, you have the right ammo, glass and you do your job you will be GTG. My Noveske 16.1 Recon is dead on and I have absolute confidence in it. YMMV.

I am beating my head into a wall over this decision. I want an accurate SPR type upper. I am torn between the 2. I know I will have a small loss of velocity with the 16 as compared to the 18, but will there be any loss of accuracy?

By the way I am also torn between a Centurion Arms Recce and a Larue Stealth 16, on the 16" side.

And a Centurion arms DMR and a Larue Stealth 18, on the 18" side.

I know I am lucky to have these decisions to make.....

Any input would be appreciated.

Jack

[jackinfl]

Thanks for the input. I have also heard the 16" is definitely not under gunned.
In reference to ammo I have addess to 3 types, XM193; Hornady .223 TAP 60 grain; and 42 gr. Federal Frangible. I am looking into trying to get some 77grain Black hills to match the MK 262 ammo...

I will probably go with the 16". Now, what length rail? 10 or 11". Bear in mind I will put a 6-9" Harris bi-pod on the front end. As far as glass I am torn between the Leupold Mark4 1.5-5 or the 2.5-8,

I was shooting yesterday with my bolt gun and I had a hard time recognizing face details at 230 yards with my Mk4 4.5-14x. I was shooting with our snipers and we were engaging photocopies or pictures of faces...

Thanks for the input, anyone that can add to what barrel would be better with my ammo that I have on hand? Larue is 1 in8 where the Centurion Arms is 1 in 7.

[rob_s]

Quit pussy-footin' around and get yourself a 6.8 like me!

I was going through the same decision when I was still looking at 5.56 uppers. What eventually sold me was researching the effective range of a 16" barrel with good heavy 75 and 77 grain loads and realizing that this was probably more than sufficient for my needs, especially knowing that the gun would still put holes in paper out past that distance.

not sure how much traveling around to shoot you're doing, but keep our location and limitations in mind. 300 yards at Palm Beach SO is pretty much the limit without a much more serious commitment to travel. And even that is very limited access for guys like me, although I'd expect you'd have an easier time getting in there.

In terms of rails, I think I'm up to a 10.0 on one of my 6933s and an 11.0 on my 6520. Let me know if you want to take a look at them.

[jackinfl]

Rob,
I can not justify another caliber... Having access to the ammo that I do it would not make sense. I was at PBSO Wednesday and shot the .308. I was gonna bust out my 10.5" to shoot from the tower but we got cut short....

"Pussy footing around" real nice

Jack

[WS6]

The 11" rail will cover the gas-block on the LaRue. The 10" will not. Protect the block and get the 11".

[crossgun]

The only thing I personally dont like about the Larue is the 1x8 barrel twist. I believe you would be better served with a 1x7 especially with the heavier bullet trend.

Something else to think about.

[USMC03]

I am beating my head into a wall over this decision. I want an accurate SPR type upper. I am torn between the 2. I know I will have a small loss of velocity with the 16 as compared to the 18, but will there be any loss of accuracy?

By the way I am also torn between a Centurion Arms Recce and a Larue Stealth 16, on the 16" side.

And a Centurion arms DMR and a Larue Stealth 18, on the 18" side.

I know I am lucky to have these decisions to make.....

Any input would be appreciated.

Jack

Jack,

Some things that may make help with your decision:

-What distances will you be shooting?
-What kind of accuracy are you hoping to achive?
-What kind of shooting will you be doing? (ie. run and gun, prone / bench, etc)?


As IraqGunz already pointed out, barrel length has little to do with accuracy.


18"
-You can use a rifle length gas system on a 18" barrel (slightly smoother than a mid-length gas system). Some companies use an intermediate gas system (between a mid and rifle length gas system on 18" barrels)
-Slight velocity gain at the cost of length and weight


16"
-Shorter, lighter, more compact, thus making it a little easier to shoot from unconventional shooting positions.
-Most will use the mid-length
-Slight loss in velocity


We all have different uses for our firearms and all have different expectations in accuracy.

This is something I wrote in reference to the accuracy of 2 different barrels based on *my* accuracy needs:

**********************************************************************


Guys always ask me about accuracy......In short, my answer is: With AR's, I NEVER measure group size. I know from years of shooting what my group size should look like at a given distance with a given optic (ie. I know my group with iron sights is much larger than my groups with a Leupold MR/T on 5x at that same distance.....but I have shot enough that I know approximatley what my group should look like considering the distance, type of optic, type of ammo, etc.).

For accuracy or group size to mean anything or for the evaluation to be "apples to apples" comparison you need to shoot the both mid-length barrels side by side on the same day one right after the other.

BOTH guns need to be

-in the exact same configuration (stocks, triggers, handguards / railed forends, etc), using the same optic (at least 10x),

-the same ammo from the same lot, a couple different ammo loadings (because different barrels like different bullets),

-the same targets,

-the same lighting conditions, etc, etc, etc.

All of the things listed above can have an effect on accuracy testing (ammo, temp, lighting conditions, rifle configuration, different optics, etc, etc, etc)

I always see guys on the internet saying my "Brand X" AR15 is so much more accurate than my "Brand Z" AR15. I doubt that 99% of these guys have done an "apples to apples" comparison between two different brands.

For *me* trying to do accuracy testing with anything less than a 10x optic is a waste of time and I would prefer to have something around 16x if possible.

In order to get nice little groups you need to ensure that you are on the exact aiming point everytime. And the only way I can do that is with a 10x (or more) optic.

*For me*, if I can hit the small steel IPSC type targets consistanly out to 425 yards with an ACOG or MR/T 1.5-5x or simular scope, the barrel is more than accurate enough *for me* and the type of shooting that I do.

The Steel IPSC targets I'm refering to are about 18" - 24" top to bottom and 10" - 12" at the shoulders. Basically it's a scaled down IPSC or IDPA target...you know the cardboard targets you shoot at IDPA or IPSC matches...also a lot of instructors use them for classes (cardbaord colored on one side and white on the other).

Here's something that makes me laugh about accuracy discussions on the internet:

For the last few years, I often use a 1/9" twist RRA 16" mid-length barrel (4140 steel / chromed lined) for my run and gun rifle matches...just a factory mid-length barrel that has been lightended almost to govt' profile under the handguards. The carbine has a LaRue 9.0 and 3.5x TA11 ACOG on it.

I have seen more than a couple guys arguing about accuracy on the internet, then I have seen those same guys come to the run and gun rifle matches (targets from contact distance out to 425 yards, smaller than normal targets) and can't hit the broad side of a barn. These individuals end up with a score of less than 10% and never come back to another match. I've seen it happen a couple times with my own eyes.



The last match I shot with Stag Arms carbine with the RRA mid-lenth 1/9" 4140 steel / chrome lined barrel (July's match, just before I had shoulder surgery), I came in 2nd place with a score of 80% and I was using 2004 vintage XM193 ammo. Pics of the match and the gun I use can be seen in this thread:

https://www.m4carbine.net/showthread.php?t=2475 (the Stag Arms gun with the FDE furniture and RRA mid-length barrel in it's newest configuration with the Magpul UBR is on page 3 ...... older pics of the same gun from a couple years ago can be seen on page 1)

Pics of targets down range can be seen in the thread below. Keep in mind that the targets on this stage are at a distance of 175 to 425 yards, there are large and small IPSC steel targets, skinny steel popper type targets, the small LaRue target, etc. *Keep in mind when looking at the pics of the targets that the pics were taken with a zoom lense*. Each target (usally 7 - 9 different targets) have to be engaged from each firing position (usually 6 - 8 different positions)....and each shooting position requires something different (ie. sometimes shooting through a port on the ground, sometimes shooting from the right or left side of the barricade, sometimes shooting over the top, etc).....you can see in the pics what I'm refering to in reference to shooting position:
https://www.m4carbine.net/showthread...highlight=TA11


I guess my point is, you can have the most accurate barrel in the world and it doesn't mean anything if the shooter is unable to use the barrel to it's full potential. And in that same breath, everyone on the internet will tell you that 1/9" 4140 steel barrels are junk and you can't hit the broad side of barn with them. Remember the old saying about "It's the singer, not the song"

To be honest, my RRA barrel that I've used in a bunch of different matches over the years (see pics in the links above) is probably more accurate than me.....especially when you consider I'm only using a 3.5x ACOG.


So in short, when guys ask me about accuracy of two different guns I don't like to answer unless I can give an "apples to apples" comparision and I NEVER go out and shoot for measured groups .........I guess my use for the AR platform is geared toward "practical accuracy", and I don't have a single AR that isn't able to hit the targets above at 425 yards with XM193 / Q3131A / Black Hills Blue Box 55 grain or simular ammo.


To anwer your question about accuracy between the Xxxxxx barrel and the Xxxxxx barrel ...... I don't think you, me, or a majority of shooters are going to be able to tell a difference in accuracy between the two barrels.

**********************************************************************

the accuracy can be great from both sizes at shorter ranges but I think somewhere in the 200-300 yard range the 16" begins to lose accuracy, this is where the 18" excedes.

This is the impression I was under so someone please correct me if I am wrong

Barrel length has nothing to do with accuracy. Depending on ammo, etc. the difference between a 16" barrel and a 20" barrel is only around 100 feet per second.

Velocity with 3 different barrel lengths using 5.56 M193 55 grain ball

14.5" barrel - 3064 feet per second
16" barrel - 3132 feet per second
20" barrel - 3259 feet per second

With this ammo, chrome lined barrels, the velocity gained from a 16" barrel to a 20" barrel is 127 feet per second......for each inch of extra barrel you are gaining 31.75 feet per second in velocity. The velocity gain isn't as great as many may have thought.

I shoot a monthly run and gun rifle match with a 16" mid-length with TA11 ACOG (3.5x) and have no issues hitting the targets when I do my part as a shooter. And I use 55 grain 5.56 ammo. 3 pages worth of pics....you can see how small the targets are toward the bottom of page 3:

https://www.m4carbine.net/showthread.php?t=2475

Thanks for the input. I have also heard the 16" is definitely not under gunned.
In reference to ammo I have addess to 3 types, XM193; Hornady .223 TAP 60 grain; and 42 gr. Federal Frangible. I am looking into trying to get some 77grain Black hills to match the MK 262 ammo...

I will probably go with the 16". Now, what length rail? 10 or 11". Bear in mind I will put a 6-9" Harris bi-pod on the front end. As far as glass I am torn between the Leupold Mark4 1.5-5 or the 2.5-8,

I was shooting yesterday with my bolt gun and I had a hard time recognizing face details at 230 yards with my Mk4 4.5-14x. I was shooting with our snipers and we were engaging photocopies or pictures of faces...

Thanks for the input, anyone that can add to what barrel would be better with my ammo that I have on hand? Larue is 1 in8 where the Centurion Arms is 1 in 7.

Most 1/7" barrels probably won't shoot the 42 gr. Federal too well. The 1/8 twist may be too fast for this round as well. Both twists will have no problems with the XM193, 60 gr. TAP, and M262.

On a 16" barrel I prefer a 12" rail. On an 18" I could go with either the 12" or 13.2", but prefer the longer rail. When resting on barricades, using a bipod, the further out you can get the point of contact the better. Hard to articulate but I notice when I'm zeroing a gun, shooting a match, etc. if I get the point of contact as far out as I can on the rail I'm more steady and produce better groups.

Glass - depends on what kind of shooting you will be doing, distances you will be shooting at, and size of targets. I often use a Leupold MR/T M2 1.5-5x for run and gun matches out to 425 yards.

Targets that you'll typically see at ranges from 50 yards out to around 400+ yards (along with LaRue targets, steel pepper poppers, 10" round gongs, etc):




I'm not shooting for groups, I'm just trying to hit the steel.

If you are shooting at longer distances and / or smaller targets, or you are shooting for small groups I would recommend something with higher magnification.

The only thing I personally dont like about the Larue is the 1x8 barrel twist. I believe you would be better served with a 1x7 especially with the heavier bullet trend.

Something else to think about.

Consider that most of your service rifles have 1/8" twist barrels on them, and many shooters have been using 75, 77, and 80 grain bullets in these barrels for years.....and they shoot them out to 600 yards

A majority of your competition shooters and 3 gun shooters use 1/8" twist barrels and a majority of those shooters use heavier bullets (75 and 77 grain).

A lot of your competiton shooters / 3 gunners practice with lighter bullets and use heavier bullets for matches.

Just my opinion, but the 1/8" is the best compromise in barrel twist between the 1/7, 1/8, and 1/9 for most civilian and law enforcement shooters when you consider the bullet weights most of us are shooting (45 grain up to 77 grain).

Many 1/9 barrels don't shoot 75's well, and none that I have ever seen will shoot 77's. Many 1/7 barrels don't shoot lighter loads (under 52 grain) very well.





S/F,
Jeff