Assuming JT's reference to the primer plate being gone means he had a blown primer...
Overpressure with a stuck case is usually the COAL being a bit too long and the neck not being trimmed to spec. Also from what I have read 375HH has sticking issues occasionally from the shallow shoulder.
Overpressure with a stuck case is usually the COAL being a bit too long and the neck not being trimmed to spec. Also from what I have read 375HH has sticking issues occasionally from the shallow shoulder.