ok, i got my ducks in a row.. i slugged my bore. cleaned and slugged, cleaned again and slugged again. then i cleaned the barrel and will call that good.
i used this method, pushed a 50 cal muzzle loader ball thru my barrel by lubing it a bit and chasing it with a .44 cal ball. i pushed it thru with a wood dowel.
the dowel deformed the .44 cal ball and not the 50 cal. here's what i got: 1 there is a tight spot about 12 inches from the chamber. 2 the grooves are very shallow in my bore. 3 my bore is a nominal .457 .. one slug read .4570 and the other read .4575 with my digital calipers. the second reading was .4575, and this being the first time, maybe i did a bit better with the second slugging. anyhow, this backs up the .458 bullets shooting better.
to further, instead of worrying about hp's i'm going to get a hardness tester and focus on bullet hardness and the mix of my lead. i can get control of leading, expansion and bullet quality, more important then hp expansion.
glenn