OK folks.
Having solved the dilemma of the IMR powder, I've run into another issue.
I ran 50 rounds of the new load to test. The AR15 blew about 90 percent of the primers out, while the Mini 14 didn't pop one single primer.
I'm running 23.5 grains of VV N-130 behind an SS109 using once fired Lake City brass swaged on a Dillon swager.
All expended brass shows no abnormal signs of a hot load (cratering, bulging, splits, cracks, etc.)
I'm thinking the swager isn't set properly, but the fact that only 1 rifle had the issue is making me second guess myself.
Any thoughts or suggestions from the gurus here?
All input greatly appreciated.