We used to spend a lot of time cleaning rifles and the only chemicals we used to use on the bore was a tiny bit of oil on a patch to stop it rusting whilst in storage. We might have one go with a barrel brush but that was it. We were never issued anything to tackle copper fouling nor was it ever mentioned by the instructors - not even to the shooting team. I can't imagine what state some of them must have been in!

Would they have done anything to them in the armoury?