Hi experts,

I'm reloading 9mm GECO cartridges (once fired) with my new 550B. Funny thing is, my S&W 5904 takes absoolutely anything the 550B produces. My Glock just doesn't. The Glock chamber seems to be much tighter than the S&W.

Approximately 25% of the loaded cartridges won't fit into the Glocks chamber. They just won't go in fully and if I force them, they get stuck and I have to pull them out.

What can I do? Change the brass (Geco to S&B or Magtech) will be my next option, as the 25% of nonworking cartridges sounds somewhat random to me, maybe the fault of the brass? I'm puzzled...