I heard a story from an BP/NG armorer/range guy that someone at his range had mistakenly (?) loaded 9mm ammo in a .40 mag. and fired it through a G22. He said he heard the different "bang" and stopped the firing. The shooter said "Gee, I wondered how I got so many shells into that mag!" Apparently didn't do any damage but created a very loud and different report. I'd think you'd get a lot of blowback around the smaller casing as well as around the projectile itself as well as no power or accuracy Has anybody else ever experienced this? Don't try this at home!