Last time I used Triple 7 was May 6, 2021. Yesterday I opened that same can that has been stored inside and has the original foam top under the plastic cap. Same rifle, same load. I used home-made caps. Shoot right at point of aim at 100-yards.
i have Pyrodex P from 1/21/21 that is opened and stored just like above. Yesterday, 2 different rifles got same point of impact as previous range session.
i have 3 revolvers loaded with Pyrodex P since March 2021. Yesterday they all fired every round into the black circle on the 10-yard target.
when cleaning, the rifle that used Triple 7 had more, thicker and slightly darker black on the patches, and it took one more pass to get to clean patches than the rifles that shot the Pyrodex. Maybe it’s the rifle.
My own conclusion is that if you store the powder in original container and put the foam circle under the plastic cap it will last at least a year without changing point of impact. Cleaning is about the same as Goex as far as # of patches until they came out clean. Lastly, loaded revolver stored inside worked fine after 10- months.
i have plenty of black powder but I tend to use it sparingly in my flintlocks and some occasions with revolvers. All of my cap rifles shoot fine with Pyrodex or Triple 7 although each shows a preference for one or the other. I shoot my shotgun a lot and use Pyrodex RS in them since it was readily available and priced good when I bought it. No issues in the smoothies.