HMMMMMM i've been thinking while waiting for the Superbowl & drinking some enginering fluid.
I take this $15 Mosin Nagant barreled stub with lugs intact that has a little Bit of erosion just barrely past the chamber and heavy pitting on the barrels exterior at about the 14" mark. I rechamber it with a 300 Win mag reamer with a .311 pilot and then cut the throat a little bigger also to get rid of the bad spot inside the barrel. I weld on a back half of $20 reciver to the stub thus making it a virgin reciver and legal to used in a pistol build. cut the barrel down to 12" or 14" and thread it for a AMD 65 or any other AK brake. add a pistol grip and go hunting. it could be single shot or load from a modifed box like the 450 Mosin. Im thinking the weight of the Mag and the extra ammo might tame it down some.
This would give me the worlds first .312 WINCHESTER MAGOSIN PISTOL FOR ABOUT $50 .
DOWN LOAD IT TO 300 WIN MAG STARTING LOADS WITH .311 BULLETS AND YOUR READY TO HUNT MOOSE WITH IT. OR LOAD IT WITH 120 GRAIN STUFF FOR VARMINT HUNTING. hell add some sabots an .223 bullets and you could likely get 4500 FPS LOL>
HMMM I need a 300 mag reamer and some time. this is completely doable especialy on a rifle but im not sure what you would gain with a down loaded 300 mag over a warmly loaded x54r??? . im looking at it to use the junk I have on hand into a hot little hunting pistol.