Good suggestions here, specially as regards storage.
Modern primers WILL degrade slowly IF the seal is broken (for example, as by pressing it into a casing) and THEN the primed casing is stored poorly. I ran into this problem when I located, completely by accident, a box of primed 8x57 which I had primed, put into storage several years before and then forgotten about. Don't like knocking live primers out, so I loaded the cases just to see what would happen. Results included half a dozen hangfires out of 20-odd rounds, one hangfire that was about a second and a half, not even the barest hint of accuracy..... but they did fire.... after 12 years of storage outdoors in an unheated shed. Primers in this case were RWS that I bought back about 1964 and finally shot off in 1977.
Should be no problems if they are stored with some attention to damp. Good suggestion here regarding dessicant gel; think I'll try it next time I lose some cases for a decade or so!
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