AR15 brass issue

[Shimitup]

Here's thought, once you get the gas block off gauge the hole and check with Ballistic on the size to make sure they didn't grab a drill for mid length or rifle for that matter. I would guess that's very unlikely but I've seen stranger things happen.

 

[Kp321]

I ran into a similar buffer problem on a mixmaster 9mm carbine. The buffer broke the retaining pin eventually. Did not know about the offset pin so turned a relief on the front edge of the buffer so the buffer would stop against the bolt carrier rather than the retainer pin.

 

[KYregular]

The issue with the buffer is definitely with the lower, it's out of spec. Pin is too far back, which the offset pin should fix. The pic with the black faced buffer is the Anderson with the pin that's off, the pic with the gold buffer (attached) is my Aero 300 AAC build and is correct. You can see there's one be full thread of difference, which is keeping the buffer from touching the BCG when assembled, which could be the cause of both problems, that's a lot of beating around. Learned my lesson, and another thing to look at while buying lowers. Also, your better off spending another $10_$15 for an Aero. First pic is of the offset pin.

 

[KYregular]

Yes, over gassed. I would go with a heavier buffer and a adj gas block. I get the occasional swipe on loading rounds if I don't push the shoulder back far enough on my tight chambers. I like the JPI adjustable gas block the best of all the ones I've tried, get less leakage.

Question on the buffer. Never seen one chewed up like that. Is that the large end that contacts the bolt? or the bumper that should bottom out on a smooth flat surface?

I think JPI makes one of those offset pins too. Should not be needed if the length of the buffer is correct as well as the BCG. The BCG should just contact the buffer taking the load off the pin. If it's not you have a problem with the BCG or something is out of spec on the buffer tube.

Lower is out of spec, thanks for the info. Made me think of that.