So, we have a “Subcaliber Mortar Trainer Device 3-F-8.” Designed by the Navy for the ARNG, to be able to train with mortars at home station.
As I recently found a reliable source for the .22 caliber blanks it uses, well, we can shoot mortars now. Safely. It came with the tech manual, but no firing tables, so, I went looking. I found a ARNG training note in Google Books that addresses that issue, and I will follow that because, well, to generate firing tables, I hafta go all ARDEC on it and shoot the thing a fair bit to generate the necessary range and ordinate data. Whee! Gunnery nerds unite!
Below is a somewhat edited version of the blurb in the note. Nota Bene item “C.”
“7 . PROCEDURES FOR THE PREPARATION OF FIRING TABLES FOR DEVICE 3 – F – 8 SUB -CALIBER MORTAR TRAINER (ARMY Reference : Operation and Maintenance Guide for Device 3 – F – 8 NAV EXOS P1185 )
a. These instructions describe a method of preparing a usable, although not exact, firing table for Device 3 – F – 8 , Sub – Caliber Mortar Trainer , Using these procedures , the following firing table data can be obtained for each charge : Range Elevation Elevation change for 20 ft . Range Change, Probable Error Range Deflection, Maximum Ordinate.
b. Procedures : [Elided because it’s boring gunnery stuff no one but me cares about]
c. Care must be taken that the ordinate resulting from the charge and angle of elevation is not greater than the ceiling of the armory. [Emphasis added]”
These projectiles are steel, have some heft, and, when impacting, fire off a black powder blank. There is no discussion anywhere on what sort of surface you are shooting *at*.
Therein might be why these things are always in such good shape when you run across them. 1SG wasn’t letting anyone shoot steel projos on his wood floor of the basketball court, and the mortar platoon sergeant wasn’t going to ding up the inspectable item by shooting them at concrete…