So I reloaded some .30 carbine rounds for my Auto ordnance M1 carbine. Well they run good, but all of a sudden the bolt will not go fully into battery. I drop the mag, lock back the bolt and notice very thin brass rings jammed in the chamber. The load is:

13.5 GR of IMR 4227
Primer Winchester small rifle
bullet 110gr sp
OAL 1.685"
Brass is a mix of PPU and Augila
And a light taper crimp
Full length re-size
all trimmed to length

Cheap brass maybe?