Good question. I really don't believe it would hurt at all. I do it quite often. Then again, I use pellets instead of straight powder. I have never had any problems by doing it. A few years ago I accidently left my ml loaded after the end of the season. When I took it out to make sure it was still on, months later, I discovered that I never shot it at the end of the previous season. I know it was a stupid mistake. I just forgot to do it. I had to shoot the gun. It shot fine. It was dead on. I just put a 209 primer in and it shot like I had just loaded it. Other than a primer in, it was loaded and sitting up for 8 months.