My 375H&H cycles perfectly when not firing, but when shooting a string it will routinely jam when attempting to chamber the last round. It appears to me that the box magazine spring is weak and as a result when firing the next to last round the recoil will slightly cock the follower (down in the rear) and there is not enough spring tension to push it back up in place. The round fired ejects perfectly but when you attempt to chamber the last round (sitting on the cocked follower) it drives up in too steep an angle and the cartridge case body will wedge between the inner lip of the right receiver rail and the step of the follower. The harder you cycle the bolt the more severe the jam.

The inner surface of the magazine box seems fairly smooth as does the follower though I will attempt to polish it some. Are stiffer magazine box springs available? Am I on the right track? Suggestions?

Thanks

Check for a slight "lip" at the rear mag box/receiver opening junction. On mine the follower would "hook up" on this. Just a slight radius on the edges of the follower cured mine.

Thanks. While trying to duplicate this malfunction from the bench, I see that there are light grind marks along the joint on the back of the magazine box. When I lightly press down on the rear of a single loaded round while the bolt is open, the rim (primer end) of the cartridge will catch along this rough area at the back of the box. There is not enough spring pressure to push the follower and round back up. I believe this is what happens during recoil. Because this round is now tilted down low in the rear the bolt pushes it forward at this tilted down in the rear/tilted up in the front angle driving it up between the rail and step of the follower.

I'm going to polish this rough area and am going to try a stiffer spring I just took out of a 98 Mauser I have. I'll post my results.

Thanks Again