I've got a couple for you. These are from when I was an army cadet. Didn't witness the first one myself tho.
We were at Beckenham shooting range during one of the inter service (cadet) comps. During a break, the cadets operating the targets (ie the ****wits that can't shoot, including me) were allowed to have a pop on the LMG. Having just been told to fire in short bursts, one female cadet fired off an entire mag in one go and the barrel went all droopy.
The other one is from when I was in "spoon platoon" as it was my first camp. We were sat in our billet busily bulling our boots, having just been shown how to do it properly. In walks the much feared colour sergeant and to his horror, one of the lads is using one of those bottle with a sponge on top polishes.
CSgt: (to the sponge polish lad) " WHAT THE ŁUCK DO YOU THINK YOU'RE DOING!"
SPL: (not even bothering to look up and with a facial expression that suggests the CSgt is stupid) "Polishin' me boots"
CSgt: (now enraged by the lads lack of respect) "COLOUR!!!!!"
SPL: "Black!"