What was the worst mistake you have ever made with a gun?

For me it was at an indoor shooting range.<br><br>I purchased a glock 23, and was shooting it and it was doing great. I put it down and put the gun it came with which was a bantam weight 1911. I shot it and I was about to put it up and I forgot that I tried to suppress the Glock but didn't have the right barrel. So I tried to shoot the 1911 with the wrong barrel. So it exploded. It was so loud it was about 12-14db which is more then a space shuttle taking off. It broke the slide and even messed up the lower receiver. I also got hit with thousands of splinters from the barrel. Luckily it was all in my shoulder and didn't go lower.