We gotta see a video of your artillery in action, MadRep!   For a second there, I thought you were referring to a cannon to either shoot golfers [somewhat frowned on in some places :)], or a cannon to shoot golfers out of ala 'human cannonball' :):):)

     But a cannon to shoot golf BALLS! Make it compact, light, rapid-fire repeating… :) you could sell them here in South Carolina, USA… :) There have been more problems with alligators taking up residence in the ponds/water hazareds on golf courses around here – a pic in the newspaper yesterday of an 8 foot gator being removed from an OCEAN beach… guess he liked the girls in bikinis :):):)

     For your next project in 'the arms race', may I suggest by-passing the potato mortar and going right to the beer can mortar.  Take EMPTY beer cans [it's not nice to waste :):)], fill with water & freeze for projectiles… I can see the 'magnum' version, caliber= Foster's 'oil cans' !!! :):):):) 

     Can hear the news cast now: "After preparing a supply of 'ammunition' for their test, MadRep and his fellow machinists staggered to the nearest golf course where they proceeded to crater every green with additional holes. When confronted by Police, Mr. MadRepillian reportedly asked for some excess golfers to fill in the holes, "You see," he said, "if we ding them with the small golf ball cannon, they won't feel a thing if we cover them up with dirt to fill in these extra holes in the greens."  Police were not amused, and the President of the district golf association speculated as to what part of MadRep's body his members were considering 'filling in' with their golf clubs."

     – Don     Not understanding golf, but definitely understanding the need to shoot golf balls :):)