300 AAC BLACKOUT 12.5 inch = 300 Fireball 16 inch?

[Garrett]

Originally Posted by alorton

I would be interested in those mags. I load long for the 300/221 and have a 7.62x40 and both prefer de-ribbed Pmags. It would be nice to get one that I didn't have to modify.

Yep - I've had best luck with P-mags as well. I've got a couple of 20-round aluminum mags that I modded as well, but the P-mags just need the rib scraped off with a sharp wood chisel.