AR-15 barrel legenth

[Pheonix]

I hope to buy an AR 15 in the next few weeks (and Kel-Tec'sd P11 and a Sub 2000). Yes, bragging! Anyways I was thinking 20" because I believe that is what I used in the army, however, I see that a lot of people are buying the 16". Why buy one over the other? What is the advantage of the 16"? What do you have?

 

[Quintin Likely]

I've got a 20" A3 HBAR Bushmaster. I want a shorty M4orgery pattern carbine someday just for fun though. I like the 20" over the M4 style or the 16" carbines 'cause of the longer sight radius and another 4" or so of barrel. The 16" barrelled guns are easier to move around in close quarters, but I don't own one yet so I can't really speak of them. I really like my 20" A3 though.

-Quintin

 

[RepublicanMan]

Bushmaster makes a Dissapator variant that has the 16in barrel with full length handguards and the full sight radius of the 20in barel.
Unless you're engaging targets beyond 300 yds there's no real net loss of performance in the 16 vs the 20.

 

[ARperson]

Plinking at a couple hundred yards or less, you could go either way and not really notice a difference. Beyond that the 20" velocity does help with the accuracy.

If you want to shoot service rifle competitions, you have to have a 20" A2.

I have a 20". I have the aforementioned dissipator model from Bushy. And I have a 24". I like them all. The dissipator is loud though.

For the average shooter, I think the difference comes down to personal preference, whether it's based on looks or weight or whatever.

 

[MiniZ]

The 16" generally "handles" better. It really comes down to personal preference in most cases.

I like the Dissapator for 20" sight radius on a 16" platform. Crappy pic, but you get the idea:

 

[geekWithA.45]

Besides the advantage the dissipator has in terms of its sight length, I've found that the slightly heavier front end helps with the muzzle rise, compared to the traditional carbine format with an AK type muzzle brake, which strikes me as quite "flippy".

The biggest diff has to to with your ammo.

Milspec ammo uses fragmentation as its wounding mechanism, and fragmentation is sensitive to velocity at the terminal end of the equation, and a shorter barrel will impart less initial velocity, which in turn reduces the range at which the round will fragment. Once the round drops below 2700 fps, fragmentation become unreliable, and you're essentially stabbing your target with a .22 caliber ice pick. (Still, your target is likely to take notice)

There is a fairly complex interaction between ammunition type, barrel length, and twist rate that needs to be understood to select the best combination for your rig.

M855 out of an 11.5 inch barrel reduces effective range to 15 meters and this is likely the source of the many failure to stop stories we're hearing from the sandboxes. On the other end, M193 out of a 20 inch barrel is good to go for 200 meters. Me, I run M193 out of a 16' barrel, which is good for about 150 meters.


Read this, and once your head stops hurting, you can be a smarty pants like me.

http://www.ammo-oracle.com/

 

[El Rojo]

Buy the 20" complete rifle and then save up $300 or $400 and just go buy a 16" upper of your choice. I just got a 20" V-Match for varmints and I am thinking about getting a 16" with red dot for some close in coyote calling. I mean the shotgun works best, but still, why not? It would be fun! Plus it is an evil black rifle and that just makes it cool.

 

[Spieler]

I currently have a 20" on mine just because I like it! And that is really what it all comes down to, personal tastes. You are not sacrificing much by going with one barrel length over the other under most circumstances. I've had both lengths on my ARs but prefer the longer 20".