ORIGINAL: Semisane
Maybe the softer material is sealing the bore better and is the reason why I got better groups with the Harvester. At any rate that's just one load. Up the charge 10 grains and the MMPs might be better.
That is what I think is going on also.The MMP are suppose to stand up to higher pressure shooting, like in the Savage Smokeless. Good to see the results of your experiments/shooting.
Chap Gleason