Military corrosive ammunition dating
However, a generous quantity of liquid media should provide enough dilution to carry away the salts and work quickly enough to prevent dezincification.
Still, if you don’t like the idea, you might clean in a dry media tumbler those fired cases that had been loaded with corrosive chlorate primers. Theories aside, the reality is that I’ve never heard of any documented failures of cases previously fired with chlorate primers that had been cleaned by either dry or wet methods – that is, failures inarguably attributable to chlorate primers—so reloading such cases after cleaning is apparently a nonissue in that regard.
These 1950s Frankford Arsenal M72 and Twin Cities Arsenal M2 Ball (left, center) 30-06 cartridges have noncorrosive primers.
Foreign made Greek M2 Ball (right), manufactured in the 1960s, also has noncorrosive primers.
While a great many people apparently believe answers to political and social questions will fit nicely on a bumper sticker, we need a bit more space for a comprehensive understanding of the corrosive primer adventure if we’re to answer such questions knowledgably.
The answer itself poses a question: “Corrosive to what? Mercuric primers, those containing fulminate of mercury, date back to 1822, when Alexander Forsyth patented the percussion cap, the corrosive igniting mixture of which was later carried over into metallic cartridge Boxer and Berdan primers.
Noncorrosive primers finally became standardized for the US military in 1949, and by 1950 all US military small arms ammo, including newly manufactured M2 Ball (and that was our original question, wasn’t it?
In trials, corrosion attacked the M1 Carbine’s polished gas piston so quickly that some were found rusted completely immobile overnight.
Exposure to saltwater weakens brass by “dezincification” where the zinc is lost (think of it as being dissolved out), leaving the copper porous (think of a colander) on a molecular level.
Logically then, we might think it a bad idea to clean cases in a liquid media which, when mixed with the fired primer’s chloride, would create a saltwater mixture.
The potential for bore corrosion and accuracy reducing pitting and rifling erosion caused by chlorate primers is real, but it is readily mitigated by immediate and proper cleaning after a shooting session.
Upon firing, the potassium chlorate in the primer becomes potassium chloride, a salt, which deposits the length of the bore.