Several years ago, on a vacation trip to my brother's house in North Carolina, my dad and I made a really nice combustion potato gun out of PVC pipe. We were launching potatoes using AquaNet hairspray at least 300 yards from our position. It was great fun. We brought the spud gun home with us and it's been sitting in my garage ever since, unused. The trigger mechanism is broken, so this week I was considering buying a new trigger so that I could get it working again. I thought I'd check with law enforcement to find out what the...