I just finished a 16" Hbar, and I need your help fellas. I put this BM 16" bbl on a Colt A1 upper, and an Eagle arms lower. The other parts had been used before since I have put a thousand or so rounds through this gun when it had a 20" A2 Colt barrell on it. The 16" bbl assy is the only new part.
Now it will shoot the first few rounds like a single shot, and eject the empties, but slams shut on an empty chamber and has to be manually charged to fire. After about 30 rounds like this, it warms up and runs just fine. It will do this with any kind of mag.
I did a gas ring check from the Army manual, checked the gas tube for center, checked the carrier key for tightness, and even put in a new tube, but it didn't help....
any suggestions...???
Thank you in advance
greco