Greg -
You have some decisions to make. Let me outline some of the issues.
N-SSA is a good group and hosts many competitions. To shoot a particular mortar or cannon with them you need to look at their specifications; if I'm not mistaken the ONLY scale replicas you can shoot is 12" = 1'. That means a full scale model from someone's blueprints of a period piece.
Next you need to look for a source of ammunition. That's been my prime consideration (since I'm not into the formal competition or reenactments). The mortars I make are in the following calibers: golf-ball, beer-can, 16/20/24oz soda pop bottle and 4" pvc pipe. That makes ammunition obviously simple - fill the container with concrete and let it rip.
Range is a funciton of heavy bullet and long tube. Longer tube (and heavier bullet) gets you out there farther. Beer cans full of concrete with a bore just slightly longer than the can will get out there 100 yards plus. Longer range for longer tubes and more powder. The 4.55" (4"pvc pipe weighing 7.5 lbs) does about 350 meters.
100 yards is a GOOD range. Lots of 100yard rifle ranges around. Not so far when one goes a little too far.
I feel much safer being able to SEE the round hit. It's pretty scary when you clear the mountain (backstop) and know the round is going to land somewhere out there in the national forrest (unpopulated but scary none the less).
Costs? $5-6-700 and up and UP. I don't think we could make another 4.5" (out of 4140 steel and industrial hard chrome plated) for under $1,300 COST.
(That's it just an inch or two to the left on the side of the screen)
