Howitzers had short barrells, and were mounted to a large-wheeled field carriage so it could be easily maneuvered on the field of battle. They were an artillery piece that had combined characteristics and firing techniques of both the cannon and mortar. They could be fired both horizontally or with high trajectory depending on the particular situation.
The howitzer was originally developed to fire bombs (powder-filled explosive shells.) This required a large bore in order to get the best effect from the larger projectiles, but it also required that the propelling charge be reduced to about one-ninth of the shell weight, in order not to over-stress the hollow projectile. Since the small charge burned so quickly, there was no need for a long barrel, and the howitzer therefore evolved into a large caliber gun with a short barrel - about five to seven times the caliber was the generally accepted figure, as opposed to 15 to 25 times for guns. Howitzers, like mortars, were chambered.
Effective range of about 750 yards or just under 1/2 mile, with a maximum of 1300 yards.
Unlike guns, howitzer sizes were measured in the diameter of the barrel's bore. Yorktown howitzers were anywhere from 8 to 10 inches.
The bomb fired by either a mortar or howitzer consisted of a hollow shell, filled with black powder and had a length of fuse that was cut to a measured length to provide a timed explosion. The bomb was rammed down the barrel fuse first. The fuse would be ignited when the cannon was fired and would explode so many seconds later. They usually did not explode upon impact as shown in the movies.