P14 Feeding Issues

[LDVolunteer]

I agree that the first impulse would be to suspect a user or ammunition fault. But, even with the gentlest close, the (unfired, of course) bullet will stay behind on opening. The ammunition is 30.06 FN manufacture with 1970's dates. I've sent hundreds of these through my M1 Garand and 03A3 Springfield with never a mis-behaving round. There is one other symptom that makes me suspect the round is being deformed by the magazine box on closing. There is always a significant dent on the shoulder of the brass after ejecting.
The date on the barrel is 8 -18 with the Eddystone "E" right above the flaming bomb over the date. The bore is sharp and bright. The bolt face will not accept a rimmed .303 round, it will only engage a 30.06 round. And yes, it's marked U.S. Model of 1917. Thanks for your consideration. mw