Leaving the powder in a Blackpowder gun

[Elbert Chamblee]

OK now the guy made his last hunt and he had the gun loaded for 3 days and no rain. He takes primer out before leaving the blind and installs a primer on the next trip to blind. He came home from Toledo and went to shoot the loaded gun and just the primer went off. He says I have been carrying a dud rifle for a few days? He puts 2 new white hots in and boom. Do you leave your BP gun loaded or shoot it after everyday? Or just dump the powder and knock the bullet out the back end. Some say put tape over barrel. Moisture must be quick to kill the black powder. What are ya'lls thoughts on this?