I've seen people's pics where they used Glad Press 'N' Seal and wrapped it around the front of the stock so they didn't have to take the barrel off.
If you use a hose to suck the water into the barrel, you don't have to take the stock off, either.
I tried a no heat cleaning solution that I've found on a bunch of web sites. Equal amounts of rubbing alcohol, hydrogen peroxide, and Murphy Oil Soap. They all come in 32 oz bottles, so you can pour them into an empty gallon sized container and shake it up. Seal off the nipple, fill the barrel and let it sit for an hour. It works, but boiling water is faster for me.I've got a length of hose so I don't have to use my kitchen sink for rifles, which is impossible for my Springfield, I have to use a step stool with my Mississippi rifle, but for the two pistols, the kitchen sink works well. Thanks to the Internet and all of you and your experience, I'm having more and more fun and enjoyment with my blackpowder guns. I thought BP would be a pain, but it's easier and more fun than regular firearms. They are now boring, in fact. BP slows you down so you can enjoy shooting more.