Daryl & smylee grouch, I have been shooting 70 grs 2fg powder, a .562 round ball, and .015 patches. Does this load combination sound okay?
When I had the .577 Musketoon, I finally went with 85gr. 2F GOEX. That is in a 48" R of T. I shot a lot of .562's with 75gr. 2F when first testing, then bought a .570" Lyman mould that cast .574". Those were the best with 85gr. 2F GOEX.
I was able to raise the rear sight to 200 yards, and smack the 200 meter steel plate, 3 times in a row offhand.
This was when teaching the new owner of that rifle how to shoot it.
These .574" balls were used with 10 ounce denim patching once I got the patches sorted out. After shoving the patched ball down the length of the starter rod, 2 fingers were all that was needed to get them down to the powder. Although the rifle had progressive depth rifling .008" deeper at the breech than at the muzzle, patches never burned and were reusable.
This .008" deeper at the breech, means the patch and ball did not go to the bottom of the grooves, let alone have compression in the bottom of the grooves, it this load put 5 into 3" at 100 meters off the bench with the rifle's battle sights. the Musketoon only has a 24" bl. The sights are crude and very close together, neither of which is conducive of good accuracy. I was happy
with that way the rifle shot. considering the loose cannon at the throttle.
I am assuming at this weight of ball, the pure lead does obturate.
IMHO, 70gr. 2F is not a good load, if you want the rifle to shoot it's best as well as being a hunting load.
Even my .50 cal. rifle demands more powder & thicker patch than that.