Overpressure in 9mm

Reloading is serious business and one should not forget that.

The reloader’s biggest fear is generating overpressure in the chamber when firing a cartridge. Overpressure can cause the gun to break (blow up) with a variety of consequences. Personally, I’m on the cautious side meaning that I don’t “hunt” for +P loads and I work up loads from minimum load data and my reloading process is tuned as much as possible for safety. Still, no-one is free from mistakes, one can only attempt to avoid them. Actually currently I also simulate my loads and check the effect of variations on powder charge and seating depth. I’m keeping pressure 15% off maximum SAAMI pressure.

But risks sometimes come from the outside… At some point in time I got some 9mm reloads from an experienced reloader. The picture shows how the cases came out of my Browning Hi-Power after firing. Clearly these were too hot for the gun and a possible safety hazard, luckily I noticed early and only fired a few rounds.


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