Went to the range and brought my AR-15, Glock 22, and SKS. Shot a few magazines of .40 cal with my Glock 22 and loaded the last mag which only had a few rounds in it. First shot I fired from the magazine felt and sounded really weak. A new round did not chamber. Dropped the mag and racked the slide. Re-loaded and fired once again. It fired again but was real weak again and the next round almost chambered but got caught up on the feed ramp. They looked like some old hollow points so I thought my Glock just didn't like the ammo. Closer inspection found that I was shooting .357 Sig through my .40 cal G22 Right before I left for the range I was making sure I didn't bring any .357 mags with me. I got distracted by my sister and I guess I did not look close enough. Doesn't appear to be any damage to the gun. I unloaded a full mag of .40 afterwards just to make sure there were no problems and it worked fine. I never thought I would make a dumb mistake like that but it is easy since .357 Sig and .40 mags are identical in size as well as the casing... I'm separating those mags in different areas from now on. I feel dumb.