The shortness of the gun would allow ease of maneuverability. The gun is a mortar, which allows a high arc (a high altitude), not precision aiming. The gun fires a 225 pound cannon ball over 4,000 yards, using 20 pounds of gunpowder. This much explosive force needs to be contained in a very thick barrel.
Why are there steps in the front of the gun?
These assist in the loading of the gun.
What is the function of the small metal loop on the top of the gun?
This assists in removing the barrel from its carriage (the base of the gun) for repair or cleaning.
What is the function of the metal rod and wheel on this side of the gun?
To rotate the cannon for aiming right to left at various targets.
What is the function of the metal rod in the back of the gun (look between the two men)?
This rod is called a hand spike which aids in changing the elevation (angle of fire) of the gun.
Why are the men wearing different hats?
The "issue" (uniform) cap is small and similar to a baseball cap. In the field soldiers preferred the wider brim hat which provided better protection from insects, sun, etc.
Why is there a line moving from upper right to lower left in the picture?
The original image was produced from a glass negative. At some time a crack developed in the negative, but a good image can still be printed.