Roger,
That is similar to what I saw with my "woodswalk load" on my GM 50 with 3F Swiss -- its a 0.018" (maybe a little less) ticking patch, a .490 ball, and ~50gr. powder. I only had Swiss for a while, as I'm cheap, but I've always thought that if the different measures required held up accuracy wise, it would be an economic break-even more or less. 50 gr. Swiss seemed quite easily the equal of 60-65 gr. Goex 3F, and even heavy loads of Goex don't give the same snap in the recoil.
I think it you want to shoot bigger loads, you need a heavier patch (even with teflon?) with the hotter powder.