I don't know about T7 but I've had a little bit of Goex 2f for about 15 years or so and it's still just as good as it was when I bought it. It's in the original can stored in thegun cabinet.I've always just taken enough out to shoot a few rounds and have never even had the can outside. Don't really know what the shelf life is supposed to be for any powder though. Shelf life has probably been expired for 10 years!