The following is from a feller who works with Austrian/Wilkinson bullet designs with the North-South Skirmish Association, Greg Edington. Greg sent me the following info...

“The .54 Austrian bullet was nominally .537 in diameter weighed 450 grains and was loaded in front of a charge of 62 grains of musket powder. The because the Wilkinson bullet for the Lorenz rifle musket was solid based it could withstand higher pressures than a minie' ball and had a muzzle velocity of 1200 FPS with the Austrian military loads. This was the highest velocity of any of the muzzle loading rifle muskets used by a major power in the 1850's - 1860's.”

As far as the other rifles, the powder (consistency/quality) used, the size/diameter of the bullets, no two designs from arsenals were exact, there would be too many variables. I have read that the standard velocity out of American .58 caliber 500 grain bullet, with 60 grains of powder, out of a 40" barrel was 950 fps.

Kevin Dally