AR15 bolt not latching back on Empty mag

[splashdown]

Ok, took out the AR for the first time. had allot of fun breaking in the barrel and sighting in the BUIS. Two things hapened wile shooting.


The BCG stopped locking back on empty mag,
I'm using a new 20rnd Pmag. the guy next to me dropped in his 10rnd mag and we could not get it to replicate the issue with using the charging handle, the issue got worse the more i shot.

The BCG stop going forward completely after about 100 rnds and I had to use the forward assist.

my nub guess is that the bolt is not going back far enough? gas block needs adjusting?
I'm using a chrome bolt if that matters in this.
also I saw on here once a thread on gun lubs that I cant find again. it was pretty comprehensive. I know its a shot in the dark but if any one has it book marked.

[tomd1584]

what buffer?
what ammo?
what is your upper comprised of? Factory build, or home built? can you list the parts? it could also be the gas block slightly off/loose.

Weak ammo and/or too heavy a buffer (or a combination) is probably where the issue is.

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Buffer is http://tdsguns.com/store/product/673...illspec-AR-15/
Ammo is PMC .223 55grain
Aroprecision upper lower
stag arms chrome bolt
Yankee hill low profile gas block