Been shooting a 625JM since about 2009. The 625 has tighter chambers than the 1911 guns I have. I have a gauge so I gauged them, the ones that fail I shot in my semis, the others for the revolver. The problem is the bulge at the base of the bullet. This makes a big difference. Last year I bought the Lee die that taper crimps and resizes the bulge. The Lee die seems to work altho some still won't pass the gauge they still seem to work in the revolver. I shoot lead, .452 to .453 diameter. If I use Remington brass I have no problems, It must be thinner than the others, Fed. seems to be the thickest, my Rem and Fed brass is old stuff, new stuff may be different.