RE: 300 Mag/Cannellure?
my 2 cents worth....ok? crimping a bullet is necessary for a tubular magazine or a revolver or ACP.......anything else (including a .375 H&H ) is not necessary.
Don't get carried away with crimping a bolt action cartridge.....it's simple not necessary.
The cannelure does help keep the jacket and lead core together however and I like cannelured bullets for that reason>