What AR15 barrel length is the most relevant.

Selected a barrel length based on the question in the OP.

  • 10.5" - 11.5"

    Votes: 36 9.3%

  • 14.5"

    Votes: 123 31.8%

  • 16"

    Votes: 164 42.4%

  • 20"

    Votes: 64 16.5%
  • Total voters
    387
TDC said:
"Most relevant" fails to address the real question. Most relevant for WHAT?

As posted, 16" gives the best combination of length and ballistic performance. Most 16" rifles are either carbine length gas systems or mid length gas systems. Of the two, the mid length offers smoother, less violent, more reliable functioning over the carbine gas. Rifle length gas systems being the most reliable as that is the original design spec. Again, depending on what you're doing with the rifle, the "most relevant" barrel length varies.

TDC
Click to expand...

1.5" difference and better ballistics? Is it really THAT much better? 1.5" for 5.56 seems hardly noticable.

I heard that the us army chose the 14.5" m4 as their standard issue instead of the 11.5" only because you can't fit a bayonet on an 11.5". Point being it had nothing to do with ballistics.

I personally think that the CF's used 16" because of another reason. Not trying to start anything up here, just my opinion.
 
By longer barrels I mean 22" + heavy barrles, I am sure a 20" heavy barrel will cause some receiver flex especially in flattops where the receiver is not as rigid as the original carry handle uppers. I am curious now though, the USMC SAM-R has a very heavy 20" barrel, I've got one in the workroom, and it would interesting to see the difference between a USGI 20" and a heavy 20"

SR-25 receivers are another matter entirely - they have about twice the wall thickenss than 5.56mm receivers. You can get away with a 24" barrel in a 7.62mm receiver - we don't do that anymore, mainly since USSOC found the 20" barrel was just as good as the 24" in 7.62mm, and with some of the new projectiles and powders coming down the pipe, I think 16" will be the next standard length for a 7.62mm gun.
 
Once again. Kevin speaks with the learned authority of the end line user. I like his idea about being issued multiple top ends, something that SF has been doing for years.

Regards
CS45
 
I haven't received my Kevin B. Doll yet........
animal-smiley-013.gif
 
Interesting thread.

As someone who's only starting to think about getting into ARs and competition, I don't even know what to look for, competition-wise, but just from this thread, I have a few ideas about what I should be looking at. Once I'm recession-free, that is...

I'm going to go see if there's a competition-specific section of CGN. In the meantime, can anyone suggest me a good forum where a civvie like me ca learn about the different competitions that'd be open to me?

I like the *look* of the 16-inch barrel, I know that much. I think that I'll try to find someone here in the 514 who'll show me his AR and walk me through it so I'll know more about what I'm talking about. :redface:
 
Originally Posted by KevinB
By longer barrels I mean 22" + heavy barrles, I am sure a 20" heavy barrel will cause some receiver flex especially in flattops where the receiver is not as rigid as the original carry handle uppers. I am curious now though, the USMC SAM-R has a very heavy 20" barrel, I've got one in the workroom, and it would interesting to see the difference between a USGI 20" and a heavy 20"
Click to expand...

I have been shooting my RRA National Match A4 for a few weeks now. The barrel is quite heavy all the way up to the start of the front post. I'd be curious to see how it stacks up to the USMC 20" in size.

It shoots better than I thought. At 50 yards, same hole. At 100 yards 3 shot groups were between .4" and .8" pretty consistentantly. There were the usual fliers that I pretended never happened. I am definitly the weak link in the accuracy equation.

right.jpg


freefloat1.jpg


group2-1.jpg
 
Brentn said:
1.5" difference and better ballistics? Is it really THAT much better? 1.5" for 5.56 seems hardly noticable.

I heard that the us army chose the 14.5" m4 as their standard issue instead of the 11.5" only because you can't fit a bayonet on an 11.5". Point being it had nothing to do with ballistics.

I personally think that the CF's used 16" because of another reason. Not trying to start anything up here, just my opinion.
Click to expand...

The difference isn't HUGE but it is noticeable. For the range, not so much, for terminal performance, it makes a difference. For the additional 1.5" of barrel(and the negligible additional weight) plus the benefits of a smoother more "rifle like" gas system, the midlength is hard to beat.

http://ammo.ar15.com/ammo/project/term_fragrange.html

TDC
 
roadkill7205 said:
Interesting thread.

As someone who's only starting to think about getting into ARs and competition, I don't even know what to look for, competition-wise, but just from this thread, I have a few ideas about what I should be looking at. Once I'm recession-free, that is...

I'm going to go see if there's a competition-specific section of CGN. In the meantime, can anyone suggest me a good forum where a civvie like me ca learn about the different competitions that'd be open to me?

I like the *look* of the 16-inch barrel, I know that much. I think that I'll try to find someone here in the 514 who'll show me his AR and walk me through it so I'll know more about what I'm talking about. :redface:
Click to expand...

Here: http://www.canadiangunnutz.com/forum/forumdisplay.php?f=57
 
RevolverRodger said:
What is the advantage of the midlength gas system over the carabine length system ?
Click to expand...

TDC said:
That's funny, a rifle length gas system has even less initial operating pressure, yet they run like a clock. I wouldn't say the midlength is civilian only in marketing as KAC, Armalite, CMMG, RRA, Sabre Defense, and Noveske to name a few offer midlength options. As for operation, I can feel a noticeable difference in felt recoil between my midlength and a carbine of identical setup. Aside from the felt recoil and lower pressures, you gain ballistic performance with any 16" barrel that is comparable to a 20".

http://ar15barrels.com/gfx/223plot.gif
TDC
Click to expand...

Check out this post, specifically the link(post #20).

TDC
 
I really disagree with swat teams and other emergency response teams using short barreled AR's for clearing houses and police raids.

So im going to say 14.5 +, no shorter
 
Personally I think that a medium (.740) contour 16" midlength is best of both worlds. Light and handy enough for closer engagements, yet more than accurate enough for longer engagements out to 500m. I wouldn't object if someone gave me an extra upper for CQB though. I'm talking purely from a combat rifle perspective, not competition.

Speaking of competition, I believe that those uber high scores at Service Rifle comps have a lot more to with using high power optics than the barrel length. Sure that long free floated barrel gives a slight edge but using a 10x optic is what really helps them kick the ass of the guy using a 3.4x Elcan. Is that in the spirit of competition? I'll let you decide.
 
You must log in or register to reply here.
Back
Top Bottom