5.7 Johnson and M1 Carbine

[floydthecat]

With some inside case neck reaming I would suspect? I made about 600 rds of 7.92 Kurz decades ago for a man with an MP44 and used Federal once fired .308. Had all the toys to work with including the inside case neck ream...

After I size, I hit the mouth with a 19/64 drill bit, but anything close to .300 works. It has to be cleaned up a tad before it can be flared or the flaring die might hang-up on the mouth edge. I don’t flare much at all, just enough to start the bullet.