My favorite CCW is my 10mm Glock-29 loaded with Underwood 115 gr. 1700 fps Xtreme Defender ammo. These rounds cost me almost $2 per round when you consider shipping. I put in lone-wolf a 10mm to .40 caliber conversion barrel and normally practice with 180 gr .40 cal. ammo that I buy in bulk from Georgia Arms. The recoil is very similar. It's in a big ammo can and I pull out a hand full of ammo at a time and load up my magazine. Sitting next to the .40 cal. ammo is an identical looking ammo can of 10mm bulk ammo that I also bought from Georgia Arms. Today I reached into the wrong ammo can and grabbed a big handful of 10mm ammo and started to load the magazine for the G-29 with the conversion barrel in it. I caught my mistake when I looked at the length of the 10mm ammo. I wonder what would have happened if had not discovered my mistake?! I think the 10mm ammo would have loaded most of the way into the .40 caliber barrel but I don't know what would have happened if the slide tryed to slam that big round into the barrel? Is there a danger that I could have accidentally exploded a 10mm round in a .40 caliber barrel? I'm sure that would be BAD if that happened, if it could have happened! I'm going to move the ammo cans further apart. Thanks for any insight/advice you can give me.