WWI French Pneumatic Mortar Bomb Note: This item is currently in storage. This is a pneumatic mortar bomb, commonly used in the trenches of World War I. This projectile was typically loaded into a short barrel, and then with the use of pressurized gas or air (pneumatics) was projected at a high velocity at a short-range target. This mortar is approximately 6-1/8 inches long and 2-1/8 inches at widest point. Donated by J.G. Jolly. Click here to return to the Featured World War I Artifacts index.