I use some good Masking Tape and cut the tape in circles, larger than the end of the barrel. I first take a pice of the tape and put it on and off the end of the barrel a few times to get any oil off the end of the barrel to insure a good tight fit. Then I use the pice I have cut in a circle for it. It will stay on through rain and snow. Yes shoot right through it with no problems, it wont affect accuracy.
My wife is also a Nurse and she brings me (finger cots) as mentioned above, I have yet to try these but other members use them regulary with the same results, Im sure there as good. But I like the look of the tape better.
(BP)