A 5/8ths scale field howitzer to shoot golf balls. 1 3/4" bore, with 200 grains of 2-FF you never see the golf ball in the air. We need to wait for the ground to dry some so we can see the dust fly when the ball strikes the ground so we can see how far and where it shoots.
PS: I forgot to say that I spent about $300.00 on materials and put in 150 hours building it. I started on it just before my shop fire in 2015 and just now finished it. Didn't have the lathe or milling machines running until a couple of months ago.