First time post, I've been reading for a while now, but have yet to answer my question. I built a new rifle, but cannot get it to run for the life of me.
The systems I've assembled contains the following:
18" Criterion Barrel with a rifle length gas system
Seekins Adjustable Block
JP Low Mass Carrier
BCM Bolt with JP enhanced rings installed
JP Low mass buffer and spring
AR Gold Trigger
The problem I'm having is the carrier is not locking to the rear on an empty mag and will not pickup the next round in the magazine. I have tried various types of factory .223 ammo. When testing I adjusted the block as Seekins advised me to, 1/4 turn at a time. I ended up with the block wide open, 4 turns out, and was still experiencing issues. For what it's worth, the gun was not even fully extracting the case until I had a little over 2 turns in the block.
I've double checked gas block and gas tube alignment, both of which appear to be in good order.
I spoke to Criterion and they were great to deal with. Their suggestion was replace all the low mass components and Seekins block with mil spec components. They believe (as I recall) my issues are related to the gas pressure still being too high when the bolt is trying to unlock, therefore the extractor is forcefully ripping the case out of the chamber and slowing the bolt down. This very well could be the problem, but my question is how does everyone else get their guns to run with low mass components? If Criterion is correct, how do I correct the timing? The rifle is for 3 gun and I would prefer to stick with low mass. I've already came to grips with the idea that this build is going to get more expensive, I just want my gun to run.
What suggestions/ideas does everyone have?
Thanks for your help.