The first muzzloader that I ever fired was an 81mm Mortar. I was in the USMC Infantry at the time.
M252 81mm Medium Extended Range Mortar
Length: 56 inches (142.24 centimeters)
Weight:
Mortar Assembly: 35 pounds (15.89 kg)
Bipod: 26 pounds (11.80 kilograms)
Baseplate: 25.5 pounds (11.58 kilograms)
Sight Unit: 2.5 pounds (1.14 kilograms)
Total: 89 pounds (40.41 kilograms)
Bore diameter: 81mm
Maximum effective range: 5700 meters
Rates of fire:
Maximum: 33 rounds per minute
Sustained: 16 rounds per minute
Elevation: 45 to 85 degrees
Pretty good sustained rate of fire for a muzzleloader! Haw!