Mississippi Gun Owners banner

AR build - 16 or 20 inch barrel?

8245 Views 13 Replies 8 Participants Last post by  osucowboy8
Well, I've decided to build an AR. I'm pretty well set on how I want it to come together. I do have some questions about barrel length though. The rifle should be relatively light and easy to handle. I'd like to make head shots on the occasional deer inside of 250 yrds but it will mostly be used as a general purpose rifle. Long range beaver kills, home defense, plinking, and zombie apocalypse type situations. The military claims combat accuracy out to about 500 yrds with the carbine. Will the 16 inch barrel really provide me with the accuracy that I'm looking for or should I step up to a 20 inch barrel?
1 - 4 of 14 Posts
We have taken deer out to 350yds with a M4 barrel and 55gr FMJ 5.56 rounds.

IF your gun can hold 1moa or better you "should" be able to take deer head shots out to 300yds in theory.. We shoot for the heart/lungs or high neck and with a well placed shot they were DRT's.
Yep.. on a 6.8 you dont gain very much FPS goin over 16"..
can get 3000+fps with a 85gr no problem thru a 16" spec II chamber
Yea it helps a 5.56 out a good bit..

"I chronographed 55 gr federal FMJ:

3140 fps in a 20"
2850 fps in a 16"

RP & WW were also pretty much the same plus or minus 20-30 fps."
only thing thats really gonna change is your drop and wind drift with a slower round. I have a DPMS 16" bull barrel and it gets pretty heavy.


It shoots pretty good, ive gotten .25" groups at 100yds with 55gr Vmax loaded with Varget in LC brass.. only shot it a few times out to 600 and 800 but i was running out of mildots :D

It shoots my 69gr PPU Match loads packed with H322 at 2850fps, and they are 3080 thru my Stevens 223 22" barrel.
1 - 4 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.