Marty, I can give you some of the velocities stated in the US Army Ordnance Manual of 1861. These are of arms in use at the beginning of the Civil War.
Rifle-Musket Model 1855: 60 grains of powder, .58 cal. 510 grain Elongated Ball (Minie)- 963 fps.
Rifle (Harpers Ferry Model 1855): 60 grs. of powder, .58 cal. 510 gr. Elongated Ball- 914 fps.
Pistol-Carbine Model 1855: 40 grs. of powder, .58 cal. 468 gr. Elongated Ball- 603 fps.
Altered Musket (Model 1816 converted to percussion and rifled): 70 grs. of powder, .69 cal. 740 gr. Elongated Ball- 879 fps.
Percussion Musket Model 1842 (Smoothbore): 110 grs. of powder, .69 cal. 412 gr. Round Ball- 1500 fps.
The Models 1816 and 1835 smoothbore muskets being flintlocks would have had slightly lower muzzle velocities than the percussion 1842 due to some gas escape through their touchholes. Part of the 110 gr. charge used in these was used as priming, so not all of the powder was behind the ball. When the percussion musket was adopted, rather than breaking up the cartridges in store and removing some of the powder, those 110 gr. rounds were issued for use with the Model 1842. The 70 gr. charge Minie cartridges were issued for use in the altered (percussioned and rifled) Model 1816 and Model 1835 muskets.
The Charleville .69 cal. musket used the same 110 gr. charge as the '16 and the '35 and it would be safe to say the the velocities were pretty much the same. In fact those muskets were patterned after the French musket. One little known fact is that the US muskets made before the M1816 were actually known by the Ordnance Dept. as Charleville Pattern Muskets. Of course when reading the figures above, you must keep in mind the variances in the quality of the powders used in testing and actual use, as well as environmental factors, although by the 1860's, care was taken in testing under different weather conditions. Also, bullet weights used in testing often vary with those used in the field. One other factor is the difference in the quality of the powders used between the Revolutionary War period and the Civil War, as well as differences between American and European powders.
I'm sorry to say that I can't be of any help at this time in giving you the velocities for the Brown Bess and some of the other British muskets and rifles, except that the P53 Enfields (used in our Civil War) are comparable to our M1855 and M1861 Springfield pattern rifle-muskets, though I believe the velocity from the Enfield is a bit higher when using English made cartridges as they used a slightly heavier pwder charge. The English Pritchett bullet was a bit heavier though and that may have brought the velocity down closer to that of the Springfield.
Hope this helps! :thumbsup: