I have shot every powder available for muzzle loading, the only powder that ever made crudring was 777 the rest are all loadable for at least 3 shots and with Blackhorn there is no limit. I believe a person should clean a gun after they shoot it and I clean my smokeless guns to as soon as I am done shooting. But I have heard it said that you and leave it for weeks with no problem,personally I would not. Lee