Large Frame AR barrel length

[Captain]

I haven't seen many large frame AR builds with barrels over 22 inches (GAP-10). If weight and portability aren't a concern for the shooter, would it be possible to run a 24-30 inch barrel, in a reasonable contour of course, on a large frame AR chambered in 308? Is there a design limitation to how much stress the upper reciver can take on the DPMS, AR-10 upper receivers? I'm just wondering why I haven't seen a 30inch cut rifled monster in a semi auto rig.

 

[BLDTYLRY]

18-20" Barrel is ideal as the additional length does not net a huge return; something like 25-40fps for each additional inch beyond 20".

 

[GBTX01]

Why would you want such a long barrel chambered in 308? If you are going to be using iron sights and want the longer sight radius I can see a point but I am having troubles seeing why you would want a 30" 308

 

[Captain]

Perfectly understandable. I shoot F/TR and some of that is bleeding into my thought process here - when it really shouldn't I think now. Mainly because I cringe when the poor .308 can't get to speed out of those short barrels and I see the 16s and 18s hit the berms and keyhole at Camp Pendleton past 800yrds Santa Margarita Gun Club. I'm actually looking at a 24in Rainier Ultra Match, it's the same price as the 20in, and in stock. I like velocity, but the more I read here the more I think actually picking the rig up and carrying it to another location would be desireable over time. I think 20 is the shortest I'll go. Thanks.

 

[GBTX01]

Knowing your background and what you expect out of the rifle will have a lot to do with what length barrel you get. I ordered a 16" JP because I plan on using the rifle predominately inside 600yds and at times CQB ranges. If I was building a 1000yd gas gun I'd probably go with a 22" barrel in a 6.5 caliber. That is a nice range you have access to. I wish I had a 1000yd range closer. Good Luck in your quest.