I was a bit embarrassed to realize after I got out of the MC that there was so much about firearms I didn't know. I have always had the interest, so I think I was quite good on the weapons we used, but most of them are way to expensive / regulated to be likely to come up in the civilian world. There was this terrible moment where I wanted to shoot an FAL and had a to get someone else to show me where the sights were...
Since then, I have spent most of my time correcting my deficiencies. Still, I think I'm confident enough to know what I know, and what I don't. The problem with the military is that you can become an expert, but on exactly one or two weapons, and little else.
PS, it's really tough to admit that particular dumb ass mistake. Hmmm... Thread topic idea... Worst firearms mistakes. We've all had a few.