This is really a very rare pre-WWII Japanese light infantry mortar that is fully function and complete with the original base plate. This weapon is currently registered as a destructive device with the ATF. This model was actually adapter and fielded in 1939 and is considered as an infantry weapon, and weighs in at approximately 52 lbs. The bore is approximately 2 3/4 across and can actually fire the U.S. M43A1 mortar rounds and has a range of approximately 2500 yards. It is accompanied by the original bipod and base plate, but it is missing the small optical sight that usually mounted on the left side of the tube. The top of the bipod still has the original WWII Japanese range plate attached with the charge settings for ranges out to 1400 meters. We assume this mortar was used as a training device after WWII, as there is a 2 1/2 X 4 inch decal on the front end of the tube that is dated September 1956 and is actually a U.S. Army Lubrication Order. As noted the tube itself is fully functional and has not been demilitarized.