Plan B - a shimmed magwell with a "caveman" modded mag release using an Aero Precision EPC upper and lower, a 16" Shooting Innovations ramped barrel, FM9 bolt, and a Blitzkrieg hydraulic buffer (much smoother recoil than with the tungsten powder filled buffer I used before). I've only run about 100 rounds of factory and handloaded FMJs and JHPs with no problems yet. Everything has fed and ejected smoothly. So far, off to a good start