Has anyone done a 223AI AR-15, it seems like the slight crush fit you need for fire forming would be problematic in a semi auto.
I have a couple uppers in 223 Ackley. Not quite 224 Valk velocities, but essentially I am getting about 200-300 fps for almost free.
The only downside is you cant load your mags all the way up. You just have to stop a few rounds from full.