Well it looks to be a headspace issue with that particular batch of ammo.

I did check the gas rings as suggested and they wern't as spread out as they could've been but looking at the spent brass there was obvious marks showing the heavy contact when the bolt rotates to lock-up. They may have been loaded with a Lee kit. I don't remember which ones I loaded with it, but wanted to get familiar with it before I needed it. Will have to check that next.

One other thing I think may be affecting my reliability is the upper is pretty new and there isn't much wear/polishing yet. Burn rate of powders may be affecting it somewhat as well.

I still think the AR's are more finicky. I've put litterally thousands of rounds through mini's without a problem. They aren't bench guns but are definately well within usable accuracy.

“You never need fear a man, no matter what his size. When danger threatens, call on me, and I will equalize.”
Samuel Colt.

�Common sense is genius dressed up in work clothes.� - Ralph Waldo Emerson