I can't imagine the mess if you didn't plug the chamber of a bolt-gun before using this stuff. Much easier with a double, after removing the barrel-group.

Its truly wonderful stuff, but you need to work out a good technique. Paper towel (or kitchen-paper for those east of the Pacific!) is worth its weight in gold when using Wipeout! These days I plug the chambers, then squirt in the foam, then quickly plug the muzzles. Saves a lot of mess.

Here's a chuckle: the first time I used the stuff on my stumpy .577, it squirted straight through the barrels, across my loading room, and formed an obscene white frothy deposit on the wall next to the phone!

Plugging the breeches is crucial for the genuine big-bores!