Cabelas and others do sell some muzzleloader condoms called Muzzle Mitts. They simply roll over the end of the barrel. I guess you could tape them in front of the sight so you didn't have to roll them over the sight, but I just roll them over the sight and cut a small slit to let the sight through.

If you have a percussion sidelock, you should buy a Kap Kover. It is a brass piece that attaches to your muzzleloader with a leather strap. Once you put on a percussion cap, you then put this over the nipple. It comes with a special nipple that has an "O" ring so that the brass cover slides down over the nipple, making it totally waterproof AND serving as a safety. With the Kap Kover in place, even if the hammer falls, it only falls on the Kover, and not the percussin cap.

As far as not hunting in the rain, I have gone hunting many times with a clear sky and it rained later in the day, so don't think that is practical, espeically when hunting in Colorado with a short season. With my percussion rifle outfitted with a muzzle mitt and a Kap Kover, I have hunted in rain and never had a missfire. I will be taking an Omega this year and will be using the muzzle mitts up front and hope their hype about the breech being waterproof is accurate.

HOWEVER, be sure to NOT bring the gun into a house or tent each night. Bringing it back and forth into warm and cold will cause condensation INSIDE the muzzle that will screw you up. I therefore leave it in a vehichle or another tent that will not be heated by heaters or warm bodies. We will be sleeping in a big tent and also have a 4 person tent set up next to it to put gear and rifles during the night.