Hunting-AR style

[van7559]

Been a while since I monkeyed with a Carbon 15. I do know they can be problematic at times and IIRC there was a slew of them that cracked at the rear pin boss but I don't recall if it was the upper or lower.
I would be concerned about the additional recoil that say a 6.5 or 6.8 would impart on the lower.
Lowers are cheap enough, why not build an alloy lower?

You really have me thinking here. Should I seriously be worried about cracking this lower? Is the recoil of the 6.8 really that much more significant?

[TrijiconJoe]

Ive never owned a polymer lower, what is the quality like?

[Colohunter]

The 6.8 does have a stiffer recoil than a 223, but it is still not bad. I have a 450 Bushmaster upper that I built on a RRA lower, I took it Elk hunting last year, but didn't get a chance to test it out. Just make sure you get 5-round magazines.

[NW CO Raptor Feeding]

You can get a 6mm X 45 wich is a .223/.556 necked up to 6mm dont have to change anything except for the Barrel. A set of dies and away you go, legal to hunt with in Colorado. Plenty of .556 brass available, and a wagon load of 6mm stuff. Probably build a complete upper in neiborhood of $450 and a set of dies will run you $30.00. Not saying its a great round to kill large animals with but will work on Speedgoats and Deer with good shot placement.