To each his own, but I would never leave a load in a gun till next year. There are definately people who have reported rust when using Bh 209. It doesn't attract moisture, but sometimes moisture is just in the air. The barrels of centerfire rifles can rust too. When I am done hunting and don't plan on using the gun for an extended period, I clean it, apply a light coat of gun oil, and then store it. Heck, I probably wouldn't even remember next year it if were loaded and with what! LOL.
txhunter58
venor, ergo sum (I hunt, therefore I am)