Mike, welcome to forum, 1970 guess your cannon and I have the same year of birth. Glad you didn't get hurt With your bamboo wire cannon. My first cannon was also made in high school circa 1986. I wish I new what I was doing and I wish my welding instructor would of new something about cannons, because what I made was more akin to giant bomb than a cannon. 3" sewer pipe 3' long , 1 1/2 lbs of smokeless shotgun powder , 1/4 plate welded to one end, bunch of wadding packed extra tight, empty propane cylinder for projectile, and lets not forget the black cat fire cracker fuse. So there we are 6 young idiots getting ready to lite the fuse to our fate. lit the fuse ran like hell only 40' away turned to see this thing go. and go it did, into oblivion. How in the hell it didn't take any of us with it is something only God Knows. At least we had sense enough to take it to a creek bottom 1/2 a mile from the nearest house. A kid I knew lived about a mile away and he said it sounded like some one threw bricks at all the windows. There was absolutely nothing left of this thing, not one piece. All that metal had to go somewhere we were all very fortunate not to be killed, there was no joy in this, no bragging about it. It scared me away from cannons for over 20 years. So I applaud your high school project It looks great I even like the carriage , which by now I'm sure is an antique. For those of you making , buying or firing your first cannon make sure it is safe. Glad to still be here. Tracy