From "Cartridges of the World", 4th Edition:
"…In appearance the .43 Egyptian looks similar to the .43 Spanish Remington cartridge. Performance is almost identical but the two are not interchangeable. The 11mm Egyptian (i.e., the .43 Egyptian- kh) also resembles and is very close to the 11x52R Beaumont in physical measurements. Early Remington catalogs list the 11mm Egyptian as also for the Beaumont rifle and it can be fired in these weapons."
The military load is listed as a 400gr. bullet propelled by 75gr. Fg black powder for a muzzle velocity of 1330 fps and muzzle energy of 1570 ft-lbs.
The .43 Spanish is also virtually identical to the .44-77; Venturino and Garbe have this comment on cartridge accuracy: "…Quite a few Creedmore style rifles by both companies (i.e., Sharps and Remington- kh) were made in .44-77 caliber, so it is entirely adequate even for 1,000 yard target shooting…". The Creedmore rifles were specially designed for target shooting so effective military ranges would certainly be much shorter.
"Classic Arms and Militaria", July/August 1998 published an article on reloading the 11mm Beaumont cartridge and notes the MV of the military load of 1476 fps with a 345gr. bullet propelled by 77gr. of black powder. The rifle had sights graduated to 1,800 m. (obviously only of use for massed area fire).
Hope this is of a little help.