Can't seem to get PMC Bronze 55gr to cycle properly on regular gas setting. Mostly FTF and occasionally FTE, last round also fails to hold bolt open. Works fine in the adverse setting.
Federal XM 223 55gr worked like a charm on regular setting.
My rifle is the 8" version. Anyone ran into similar issues?
I think you have you're answer, and just need to note what ammo prefers what setting. Different ammo brands and weights will use different powders with different burn rates. Could be that PMC bronze produces some combination of: too much pressure, not enough gas, too fast of a burn rate for the barrel length.
The action is most likely still settling in? How many rounds have you cycled through the rifle? Rather than sanding and polishing, I've always been of the school to just keep everything that moves wet, sooner or later it will lap and polish itself to where it needs to be.
After 300rds and regular cleaning things got buttery for me both 5.56 and 7.62. You see wear on the carrier rails, carrier where it slides across and firing pin retainer on back of carrier. Not to mention the bolt lugs probably mate in a little too.





















































