while it is true that they make great muzzle protectors, there are much cheeper alternative products made specificaly for that.A few years ago I cut off the end of my left fore finger. The hospital dressed the wound and said don't get it wet for a few weeks. So I stopped by the drug store and ordered a box of extra large condoms (the regular or large size wouldn't fit over the bandages). I would roll one over my finger and then take a shower without getting the bandage wet. Also, you can put one over your rifle muzzle to keep rain out, and if you have to fire real fast, you can just shoot right through it without hurting anything.
Don't forget that if you run out of condoms you can always fall back on the really old fashion remedy of using sheep intestines with a knot tied in the end.
Of course the intestines should be out side of the sheep... i would imagine they get a bit miffed when you stick your weapons in them while they are still alive (unless your into that kinda thing, in which case just keep that info to yourself please).