Thats interesting, I think that we will find different powders will work best with different primers it really would not suprise me if the 25 apc or one of the lower primers were to work best with 777; I believe that the oposit will be true with BH 209 as it is a progressive burn powder and needs pressure to burn right. Starting the atright pressure may well be the key to a consistant burn which would give the same barrel whip and there for the best accuracy. At least thats my opinion. Some of us used to do this back when there was a dozen different brands of caps available and I was building Hawken rifles for sale. Lee