AR Barrel Length

[msalm]

If going with a straight prairie dog rifle, I like the 24" for the heavier forward weight, and they shoot very well too. The 20" is a good standard and I like a standard .750" gas block for a decent handling rifle. For calling coyotes I built an 18" barreled upper with a .675" gas block and a tapered barrel under the handguard. For as skinny as that barrel is it still shoots 3/4 MOA and is very light and handy with the ACE skeletal stock on the lower. I tend to choose barrel profiles more on the intended use as far as heft and balance vs. any perceived accuracy/velocity gains.

[load]

Originally Posted by trebark

Putting a 24" barrel on an AR is like jamming a square peg in a round hole. Ballistically, you gain little with the extra 4" of barrel if the shots are 400 or closer. As a result, go with 20" for that matter 16" would work just fine too.

the problem with long range accuracy and short barrels with large for caliber powder columns is velocity spread. a 16" 223 has a horrible spread and will string vertically at distance. the 20 is better (minimum recommended for full burn) and a 24 is even better.