I tested mine out last year by leaving it loaded for 4 months. Put a cap in it and it fired right off
.
Like said above, try to keep the barrel from condensating and I think you will be ok. I leave mine loaded all season until I shoot something (two weeks max, but I usually shoot something in the first three days). Half the time I just leave the thing in the blind and lock it when I leave if I am coming back the next day or later that day.
Check your local regs as well. In MI it is not considered loaded unless there is a cap in it. However it is still a danger and should be treated that way. With pellets you could probably just pull the breach plug and dump them out the back. As long as you don't crush them when you load it. Then push the bullet back out the front.
Paul