I just acquired an M1898 in great condition.  I would like to use it in CMP Vintage Rifle competition, but I am having an occasional feed problem.  The cartridge rim appears to jam as it comes around under the bolt.  The bolt will not move forward, as though it has been somehow locked to the rear.  If I open the loading gate I can push the offending cartridge down, then close the gate and everything is usually OK.  Any ideas?