And if you want a
really reduced load try a roundball and 5-6 grains Bullseye or equivalent. Lube the ball with liquid alox and thumb it into the case neck, or thumb it in dry and smear some bullet lube around the circumference. Either way works.
Select a ball mold (or a lead buckshot) that'll go into a fired case with some thumb pressure, tight enough it'll stay put until you stick it in the gun. Something that diameter will be sufficient for this purpose.
De-and re-cap the case. Don't resize it. Dump the powder charge in, seat the ball, and shoot it. Betcha you'll hit at least a half dollar sized target at 50 feet, probably better.
I do this sometimes with .30-40 Krags, with antique (collectible) equipment because, well, I like to.
The mold for .30 balls is an original Frankford Arsenal mold made of bronze and dated 1895. Fairly heavy, weighs a couple pounds. (They issued them to Army units in the 1890's for gallery practice.):
De- and re-capping done with a more modern tool, also made by Frankford Arsenal (the real one not the modern day one), in 1909: