I've been struggling with a persistent problem which I just can't seem to figure out or eliminate. Working with Rem brass in 338 RUM: all brass is fully prepped including a careful uniforming of the primer pocket using a Sinclair carbide pocket uniformer, which is non-adjustable priming with Federal 215M's which measure .127-.128 from top to bottom i measured the cutting portion of the tool and get .130" pockets seem to measure .130" deep after uniforming with the tool, as measured with the tail end of my digital calipers THE PROBLEM - I seat the primers using the priming arm of my Rockchucker press. I have considerable leverage while using the press and can feel the primers bottom out. However, when I place the loaded cartridge in the calipers I can clearly see light all around the protruding primers. Place a cartridge on a piece of glass and it wobbles slightly. I have tried to use more force than is appropriate to further seat the primers. This will cause a slight flattening of the primer head but does not eliminate the problem. Exactly what am I missing here?