Looking at getting either a 13.7inch or 14.5 inch with a short can max overall length under 17 inches. Rifle is going to used for ranges between 0-400 yards. Im in the UK so the having to adhere to the min 16inch barrel length does not apply. After some research the 13.7 inch barrel has 66fps (62gr ss109) less then a 14.5inch barrel. At 500 yards the difference is 48fps. Will the 66fps more velocity from the 14.5inch barrel going to make much difference for range and accuracy ?
13.7 INCH VS 14.5INCH AR RANGE AND BALLISTICS
- Thread starter sharpshooter82
- Start date
What are your expectations at 400? Short barrel and SS109 is a big ask at that range. Poor choice for target or hunting.
What distance will be most of your shooting? Is 400 a priority or edge case?
Are you only punching paper or do you need energy at impact to kill?
What optic and ammo?
Velocity helps, so simple answer is longer is better.
But if it is worth it, depends on your goals.
What distance will be most of your shooting? Is 400 a priority or edge case?
Are you only punching paper or do you need energy at impact to kill?
What optic and ammo?
Velocity helps, so simple answer is longer is better.
But if it is worth it, depends on your goals.
Expectations at 400 ; practical shooting comps / accuracy
Most of my shooting will be mainly cqb type and 0-300 yards with the occasional 400 , I have an AR-10 for the long distance stuff
Paper punching ammo mainly ss109 62gr unless I can get 77gr
Optic will be vortex razor 1-10
SS109, at least what we get on store shelves here in the states (xm855) is pretty awful in the precision department. You can probably eke out the occasional 2moa 5 shot group, but it will throw fliers into the next area code. My experience has been that it’s more realistically 3-4 moa in larger samples (10 shot group).
As to the barrrl length, run the velocity numbers through a ballistic calculator like Strelok. My guess is the difference of 40-70 fps is well within the noise of 3 moa ammunition.
As to the barrrl length, run the velocity numbers through a ballistic calculator like Strelok. My guess is the difference of 40-70 fps is well within the noise of 3 moa ammunition.
66fps can be within the variance between a slow and a fast barrel of the same length.
Barrel length, by itself as a variable, really doesn't have a whole lot to do with accuracy/precision. A 6" barrel can be more accurate than a 20" barrel.
SS109 sucks ass unless you specifically need a penetrator.
I'd say go with the 13.7" - you won't see a difference in your application between that and a 14.5" - to end up with a slightly shorter overall rifle with the suppressor on, and shoot something better than SS109 if you want anything that could be called accurate.
Barrel length, by itself as a variable, really doesn't have a whole lot to do with accuracy/precision. A 6" barrel can be more accurate than a 20" barrel.
SS109 sucks ass unless you specifically need a penetrator.
I'd say go with the 13.7" - you won't see a difference in your application between that and a 14.5" - to end up with a slightly shorter overall rifle with the suppressor on, and shoot something better than SS109 if you want anything that could be called accurate.
It's been a while since I cared about muzzle devices but last I checked 13.7 was just dead air key keymo stuff and surefire.
14.5 will give you more options for a pin/weld, often weighing less. No real diff in ballistics so just go with the muzzle device you want.
My preference is 12.5 middy with a direct thread can. They're all about the same anyhow.
14.5 will give you more options for a pin/weld, often weighing less. No real diff in ballistics so just go with the muzzle device you want.
My preference is 12.5 middy with a direct thread can. They're all about the same anyhow.
GGG SS109 is actually pretty accurate stuff their m80 ball is very good . Off course their match ammo is a lot better and is available here as well
Would the extra 66fps from the 14.5inch barrel give any mean-full advantage ???
12.5" could do it too
Barrel quality is the big one, a nice stainless barrel will give better velocity and last longer vs a cheap chromoly
UK so straight pull I'm guessing? And are you allowed to rebarrel it yourself like we do here in the states or does all the work have to be done by a licensed gunsmith?
I wholly understand what you're looking for. I am of shorter stature and prefer an AR that is easier to manipulate.
I do a good bit of shooting out to 400 yards. There was a time when I had one each of an 11.5, 12.5, 13.9, 14.5 and 16" barrels. I also shoot a lot of m855 and various 77gr loadings.
I haven't done any formal testing, but something I have noticed is that differences in performance among the differing barrel lengths did not become meaningful until the differences in velocity approached 300 feet per second. Put more plainly, when starting with an 11.5" barrel and increased barrel length and took note of performance increases, I did not see a meaningful increase in performance until I got to a 16" barrel where the velocity increase amounted to about 300 fps. I now run two setups. An 11.5 and a 16".
I run the 11.5" barrel with a YHM Fat Cat suppressor. The Fat Cat is one of the shortest suppressors you can get for a 5.56 and my setup measures just over 15".
If your decision is one of choosing between a 13.7 and 14.5, go 13.7. The difference in velocity is negligible. I just don't think you're going to meet your length goal with a 13.7.
If you decide to go shorter, consider the 12.5 rather than the 11.5. From a performance perspective, the 11.5 is fine, but even I feel a bit cramped by the limited space on the handguard. The extra space you get with a 12.5 is very noticeable..
You can also do a bit of velocity loss mitigation by going with a "fast" barrel. Some barrels typically get more velocity than others. For me, I've had good luck with Criterion barrels. Proof barrels run pretty fast as well.
I don't know what your budget is, but check out the Cobalt kinetics direct thread suppressor. It is very light, fairly short and performs very well. It is also pretty expensive. I like my Fat Cat. It's very short and performs very well. In terms of sound mitigation, it is one of the best I've heard. The downside is that it is gassy. A method of gas regulation was necessary.
No. I'd also say the average velocity loss is closer to 30-50fps than 66 anyway.
I wholly understand what you're looking for. I am of shorter stature and prefer an AR that is easier to manipulate.
I do a good bit of shooting out to 400 yards. There was a time when I had one each of an 11.5, 12.5, 13.9, 14.5 and 16" barrels. I also shoot a lot of m855 and various 77gr loadings.
I haven't done any formal testing, but something I have noticed is that differences in performance among the differing barrel lengths did not become meaningful until the differences in velocity approached 300 feet per second. Put more plainly, when starting with an 11.5" barrel and increased barrel length and took note of performance increases, I did not see a meaningful increase in performance until I got to a 16" barrel where the velocity increase amounted to about 300 fps. I now run two setups. An 11.5 and a 16".
I run the 11.5" barrel with a YHM Fat Cat suppressor. The Fat Cat is one of the shortest suppressors you can get for a 5.56 and my setup measures just over 15".
If your decision is one of choosing between a 13.7 and 14.5, go 13.7. The difference in velocity is negligible. I just don't think you're going to meet your length goal with a 13.7.
If you decide to go shorter, consider the 12.5 rather than the 11.5. From a performance perspective, the 11.5 is fine, but even I feel a bit cramped by the limited space on the handguard. The extra space you get with a 12.5 is very noticeable..
You can also do a bit of velocity loss mitigation by going with a "fast" barrel. Some barrels typically get more velocity than others. For me, I've had good luck with Criterion barrels. Proof barrels run pretty fast as well.
I don't know what your budget is, but check out the Cobalt kinetics direct thread suppressor. It is very light, fairly short and performs very well. It is also pretty expensive. I like my Fat Cat. It's very short and performs very well. In terms of sound mitigation, it is one of the best I've heardThe downside is that it is gassy. A method of gas regulation was necessary.
As for m855, I do hear a lot of people say that they don't get good performance with it, but I've found it to be more than adequate for shooting steel out to 400. I shot the following groups at 100 yards with my 11.5 using a 3.5x ACOG. The target dots are 2" in diameter.
The group on the left was shot with Winchester m855 and the one on the right was with PMC m855. These are pretty typical of what I get with each respective ammunition.
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I don't think so. For a general-purpose AR in 5.56 (and I'm sure someone will hit me with a hammer for saying it), I don't see much point in anything other than 11.5" (with a can), 16", and 20", ignoring things like very specific purpose-built rifles, varmint, and barricade benchrest/PRS stuff.
Handguard space can get a bit cramped but I have a 7.5" 300 Blackout with a 9" handguard and don't have much issue with it. I'm not mounting accessories on it that cost more than my truck which would warrant more real estate, as a disclaimer.
I would say pick whichever you think suits you best. Shooting out to 400 you're probably not going to see a difference between the two barrel lengths and even then, they're so close in length that you could get a 13.7 that shoots way faster than a 14.5. My buddy and I both shoot 14.5's and his Geissle shoots about 40 fps faster than my Colt.
I'm also guessing that if a manufactory states sub MOA / 1 MOA for their standard barrels - including 14.5inch , there would no MOA loss at 13.7inch ???
There shouldn't; everything else staying the same, the shorter barrel is more rigid and from a completely theoretical standpoint, would be more likely to be more accurate (ignoring barrel wave harmonics, etc related to barrel length).
Read the "MOA guarantee" with an extremely jaundiced eye, most of the time they're written something like "1 MOA guaranteed for first group only when using this specific ammo for a 3-shot group with the rifle clamped down into a lead sled".
