What seems to be true is if you seat the ball to the point that it just rests on top thepowder column, you get the sort of consistent spreads I show with that 45 grain load. It is possible to compress 777 quite a bit and that's where I've had erratic velocity spreads.
where 777 really came in for me was a 15 grain charge under a .433 ball in a Lepage replica. There was no fouling build up and accuracy was on the order of a Smith k22. As I recall, the velocity was the same as with pyrodex thrown from a measure calibrated for 20 grains of goex fffg.
