Chlorate/corrosive priming


What are the advantages of Chlorate (corrosive) primers versus the newer non-corrsive mixtures? I know the US changed over to all non-corrosive priming in the early 1950’s or so, but many other countries, especially in the Communist sphere continued to use chlorate primers for many more years. Why? Are any countries still using chlorate based primer mixes?




The changeover from corrosive to non corrosive was not a smooth one that took a simple change to complete. Some of the early mixtures were not stable, some deteriorated rapidly. There were problems with the non corrosive mixtures being not sensitive enough or being too sensitive, the early NC mixtures tended to be more brittle and subject to crumbling (hence the foil disc to keep the mixture out of the powder), and there were different seating requirements between the Boxer and Berdan systems. The sensitivity problems still haven’t been solved completely, witness the special milspec primers for use in some automatic weapons.

Maybe some countries weren’t able to address the problems as quickly as others and simply chose to wait. I don’t know. Just a guess.



Ray - thanks for the interesting answer. I never realized there were reliability issues involved in the changeover; always assumed (very dangerous practice) it was more a matter of having a proven system in place and no need / desire to switch horses in the middle of WW2. Also always thought the milspec primers was an issue of cup thickness / hardness. Thanks for the enlightenment!



You may well be correct that the MIL SPEC primers differ only in cup thickness. I should have put my customary CYA after my statement. Here’s what CCI says. Maybe I gave too much weight to the “sensitivity” part. If somebody has MIL-P-46610E maybe they can read it and tell us.



I tried to be a chemistry teacher back before the turn of the century, and worked in a chemical factory for a time, but never with explosives. I have done some limited reading on primer chemistry and from the processes listed, I would guess that production of chlorate primer compounds would be much easier, much lower tech than the production of of lead styphnate non-corrosive primer compounds. Remember, the Soviet Union was a place of permanent material and production shortages. A nice simple process like mixing chlorate primer compounds would eliminate one kink in the production pipeline. Chlorate primer compounds can be mixed from relatively easy to handle dry ingredients as opposed to non-corrosive mixes that use lead styphnate which involves a more complicated chemical process. In a nut shell, you can make chlorate primers if you can read a cookbook, but you need a skilled chemist to make lead styphnate. Chlorate primers have some good points and it may have been easier to chrome plate bores and train recruits to clean their weapons than to switch to a new and touchy process.