and was likely fired within a single season of manufacture, so no temperature cycling.
i have seen ammo, made in the same year (1955) in the same plant, stored in 3 locations after being sold surplus for 20 ish years, the stuff stored in a big tupperwear container in a shed outside had about a 10% failure rate, 10% hangfire rate, and the rest shot erratic groups, the stuff stored in the basement of an occupied house, and the stuff stored in a shop with insulation and limited heating durring winter (above freezing most of the time) both shot ok, but had a few rounds go click, bang
its not a big deal short term, but dont count on ammo stored that way for a decade, it will probably go bang, but i wouldnt bet my life on it
