In handloading for fifty years (damn that sounds old!), never had any defective primers, except for Winchester.
In addition to several good ideas posted above, could the brass be resized too much causing excessive headspace? Do you have some gauges to compare fired brass to the resized brass? The shoulder should not be set back more than 0.005”, and 0.0015” - 0.003” is the optimal zone.
In addition to several good ideas posted above, could the brass be resized too much causing excessive headspace? Do you have some gauges to compare fired brass to the resized brass? The shoulder should not be set back more than 0.005”, and 0.0015” - 0.003” is the optimal zone.