In my youth eons ago we used to shoot .303 SMLE rifles on range to 600 yards .The ammo was standard military issue with cordite and primed with berdan primers. The first job at the range was to light a fire under a small tank to boil water. After the shoot we would pour 2 jugs of boiling water through a funnel through the barrel before pusing the first patch through.We then brushed the bore with a stiff bristle brush with boiling water, and finally dry patches until the barrel was bright and shiny. this followed by a light military issue gun oil. I do not recall ever seeing copper fouling or any barrel defects even after some thousands of rounds being fired through those rifles. I just wonder if I am missing some thing here as I have not heard or read about this method of cleaning for years. g