Funny story - I once bought some really awful 9mm ammo for my beretta 92. it was really cheap (440 rounds for 20 bucks!) because it had a wax bullet with a small BB-sized ball bearing at the nose. it was supposed to be just as accurate as the real deal within 50 feet. well apparently the ball bearing wasn't always centered, and the wax would melt as it went down the barrel (or something). the BB would bang around the rifling, causing numerous dents and pits in the barrel
after I discovered that, I was seriously pissed off. it wasn't the smartest thing to do, but I swept the rest of the rounds off the table (This was in a wooded backyard, not at the range - I would NEVER do this at the range), stepped back about 20 yards, and just went to town on those things with everything from a .22 to 10mm.
anyway, none of the rounds actually detonated, but I ended up with a HUGE mess of spilled gunpowder and obliterated cases. I sure did feel better after that!
The best (or worst) part is that I covered the mess up with dirt and promptly forgot about it. About a year later, I decided to build a bonfire that just happened to be in the exact same spot
I must've jumped about 30 feet in the air when the first round cooked off!
I could've sworn I left my shoes right there at the fire. anyway, the point is that nothing really happened when i shot that ammo, although I would NEVER do it again, and would never recommend someone else do the same. because if it all goes as planned, it's not that interesting, but if something does goes wrong, you have serious potential to injure your property, yourself, or others. It's just not a responsible thing to do.