gamestalker
member
Years ago my Wife and I lived in a home that had a swamp cooler rather than refrigerated AC. I hadn't been reloading very long at that point, maybe year or so. I loaded up about 300 shotgun shells using data I had already loaded with prior to moving into this home that performed very well. Anyway, about two weeks after having loaded these shells I went shooting and quickly discovered I had a major problem. My shells wouldn't eject from my 12 ga. 870 and showed high pressure signs on the primer as well. I took them home and proceeded to take them apart and discovered every single one had a single lump of hardened powder instead of normal flaky powder charges. I put all the powder charges into a glass bowel and used a wooden utensile to break the powder up into it's normal flaky consistency and reloaded all the hulls with the same identical charge. This time though I had installed a window AC unit in the room which eliminated the swamp cooler humidity. When I went back out to shoot those reloaded reloads, every single one performed perfectly normal.
I would never had thought that humidity could have that extreme effect on powder to the extent I experienced. Now days I'm always aware of how much humidity I'm reloading in and never, ever load with a swamp cooler running in the house. I sometimes wonder how extreme the pressure difference would have been if I had been loading metalic, like .357 magnum? I fear that could have effected the powder enough to cause a catrostrophic pressure spike in a metalic load.
So keep your primers and powders in dry storage, and load in a dry enviroment to avoid unpredictable issues. The powder that lumped up wasn't exposed to the humidity for more than a couple of hours, maybe 3 hours or so.
I would never had thought that humidity could have that extreme effect on powder to the extent I experienced. Now days I'm always aware of how much humidity I'm reloading in and never, ever load with a swamp cooler running in the house. I sometimes wonder how extreme the pressure difference would have been if I had been loading metalic, like .357 magnum? I fear that could have effected the powder enough to cause a catrostrophic pressure spike in a metalic load.
So keep your primers and powders in dry storage, and load in a dry enviroment to avoid unpredictable issues. The powder that lumped up wasn't exposed to the humidity for more than a couple of hours, maybe 3 hours or so.