The round is going above the chamber, and pushing the bullet into the case. The bolt also runs over the top of the case and crushes it. I didn't have my phone at the range but this pic below gives you an idea of what's happening.
Attached FileRecently changed the barrel on this upper. Ran without issue before the swap, only parts changed were the bolt and barrel. WOA barrel and BCM upper. This has happened with three different branded mags that have functioned fine prior. This also happened with three different types of ammo, black hills, federal and AAC. The bolt catch has kept the bcg open every time it is ran empty. Non-adjustable gas block, dimpled barrel. Rifle is mostly ran suppressed, but did function the same unsupressed. Ejection at about 2 o'clock. The failure only happens once every 60 rounds or so.
Below are the feedramps. The reciever's cuts step down into the barrels cuts slightly so there is no lip to get caught on.
Attached FileHere I circled the area that the round is being pushed up into inside the extension
Attached FileWhat issue am I correcting here? Wouldn't think feed ramps are causing it since there's no lip to catch on. Being the only variable was the barrel my head is telling me it's likely gas and short stroking once every few mags. That seems weird to me though because it does lock open every time it runs a mag empty and it ran the same without the can. Since the gas block is non adjustable, should I try tossing a Carbine buffer in since it currently has an H1? Or maybe it's overgassed and outrunning the mag and I should try an H2?