Originally Posted by rt4x4
No ever have done this, any type of 300 blackout upper?
Earlier this year I installed a CBC Industries 300 Blackout complete upper from Sportsman's guide on my Bushmaster lower. Fits perfectly and functions flawlessly. It's a 16" pistol gas system. You can use the same BCG and mags as for the 5.56. I went ahead and purchased a new BCG for it tho.
It shoots pretty well. These two groups were at 100 yards. The top group was first, then I gave the scope two clicks down for the second group. Nikon P-223 3x32 BDC.
I recommend this BCG from PSA. It's probably better than the Ruger AR556 BCG anyway. http://palmettostatearmory.com/palme...roup-8779.html