I set up a 10.5" AR pistol recently (5.56/.223) as an 80% build (this is not my first 80%), with a factory upper and upon testing it, I got about 20 rounds through it before I started getting light primer strikes (light enough to see a faint mark, but not strong enough to even hear any click of the trigger/hammer) with every round the gun would chamber. It shoots the first shot that I manually chamber with the charging handle or bolt release, but every subsequent shot has the aforementioned issue. Here are the things I've tried: - Complete de-lubing and light lubing. - Different BCG. - Holding the bolt catch release down while shooting (this was an issue on a previous build that necessitated the slight filing-down of the catch). - Using the forward-assist button. - Different types of ammo. ^^^All of these have had ZERO effect on the issue in question. Again, if I manually cycle the BCG, that round will fire without issue. So, overall, when it cycles, it will successfully load a new round and eject the old one, but the new chambered round will receive a light primer strike and will not be set off. Has anyone encountered a similar issue? From those I've talked with already it sounds like either a hammer/hammer spring issue or a gas issue. How do I go about troubleshooting this more?