Tks for the mention, Mark.
Rice is pretty spot-on with their bore sizes being right.
.015" deep rifling would make your .530" groove to groove measurement correct.
I have a similar barrel to yours, but made by Don Getz, many years ago, with quite deep round bottom rifling and a .500" bore. Unfortunately, the lands in my barrel are
wider than the grooves, however it still seems to shoot well.
I use 85gr. 2F and a .022" canvas patch, or a 10oz. denim patch with both cast and commercial swaged .495" balls. These patches have some scorch marks on them
but with that load of 85gr. 2F GOEX, do not burn and do not allow fouling to build. I am using a wet water based lube patch. WWWF + a bit of oil to slow evapouration
in the summer time heat.
An alternative to the .495" ball and perhaps a better solution would be to use a .490" ball and a 12oz or 14oz denim patch. I measure 12oz denim at .030" and 14oz. at .034" using calipers
compressed hard on the cloth.
.490" + .030 + .030" = .550"- which should give a really snug fit in the bottom of the grooves - .010" compression in the bottom of each groove.
My loading of a .022" canvas patch runs .459" + .022" + .022" = .539" which is larger than my groove dia. but still scorches, thus it is not tight enough to hold the pressure back as
there are small brown streaks on the groove marks of the patches. These small brown marks are scorches. Brown, not black. The patch is still reusable, just not as snug as works best
for me. It does work, though.
