My P14 bolts fit the 303 rimmed cartridge and I can use the P14 bolt for belted magnum case heads like the 300 Win Mag. When I use a M1917 bolt for a magnum belted case head I have to open the bolt face and then there is the large Mauser type claw on the 1917. And then there is the smoke hole, the hole came later.

F. Guffey