Scalplock:
Authentic reproductions of Civil War rifles shoot high because the sights they replicate were designed to shoot high, to maximize the range at which a rifleman in the ranks would be likely to hit a man-sized target by aiming at the enemy's belt buckle.
In the North-South Skirmish Assn., we shoot these firearms with great success at clay-pigeon-sized targets at ranges of 50 and 100 yards using powder charges ranging from 35 to 60 grains of 2 or 3fg. We have solved this accuracy problem by installing higher front sight blades.
We file off the barleycorn-type front sight down to its base, if it has a base, or to the barrel if it does not. Then, if it has a base, we file a groove in that base and solder in place a new front sight of soft iron or brass about half-an-inch high, half-an-inch long and 1/16th to 3/16ths of an inch thick/wide. (If no base, we simply solder the new sight perpendicular to the barrel.)
This sight, when first fired, should place your point of impact BELOW the target. Elevation is then attained by filing, a little at a time, off the top of the new front sight and trial shooting until the point of impact raises into the target at your preferred sight picture -- 6 o'clock, center hold or 12 o'clock.
If you go this route, you will want to make or purchase a front sight protector, which is kept in place when the gun is not in use to protect the higher blade from side impacts that could bend it or knock it off. But actually, properly done, these front sight replacements are quite sturdy.
If you prefer to keep your musket with "original equipment," I fear your only solution will be developing advanced skills at "Kentucky" elevation. Lowering charges to compensate for a 12-inch elevation deficit would not be practicable. :imo: :m2c: :blue: :grey: