15 Feb 22
Comments on blown primers, from friends, students, instructors:
“Any time 5.56 brass is reclaimed for reloading, there is a risk of getting cases that are from 5.56-level ammunition, but that were fired in .223 chambers.
The combination of 5.56-pressure ammunition fired in a chamber with .223-spec freebore and throat tends to cause a ‘high-pressure event’ (pressure spike) that can expand the case head permanently to the point where it will no longer reliably hold a primer.
When such a case is modified to 300 Blk, it could very well lose a primer in the normal course of extraction and ejection.
300 BLK can be loaded hot enough to ‘pop’ primers in any event! It’s pressure spikes that cause the problem, and any case can be loaded ‘too hot.’
When primers start flattening/cratering, pressure is too high for reliable primer retention!
Reloaded ammo should thus be loaded only to moderate pressure, and used exclusively for non-serious purposes!”