Interesting AR Failure

[bigblue]

The steel ammo, specifically Tula, has much faster burning powder than can result in short stroking if the gas port is too small.

Bottom line, there isn't enough data here to solve this. The failure to BHO could have just been a light round combing with a slightly under gassed system and a weak mag spring pushing on a worn preban follower. Too many variables.

 

[mac1911]

Nothing wrong with stag stuff. Parents company is continental tool and machine. They manufacture for Colt and many many others.
I would check to make sure your bolt catch spring is correct. As noted isolate magazines and take that offer to swap to a known good upper/lower. I fired 200 rounds of tula Sunday through my RRA A2 not a hick up. Actually accuracy was less than good.
Take a real good look at the bolt catch edge make sure it's not chipped and is grabbing evenly.
I think I kept my bad one......if so I will post pics.

I had a simular issue like this . The bolt catch was binding and was only catching a small portion of the nub that grabs the bolt. I just grabbed a catch I had and replaced it and all was well.
https://m.youtube.com/watch?v=vCKR8jBUTHw basically what mine was doing.