Hello, looking at your post, sounds like you might have lost your neutral line to the house and everything is trying to operate off the ground. You need to look at the connections from the pole to the meter socket or better yet call the power company, it might be behind the meter, that's where I...
I guess if you get it to fire and leave the barrel, no air only obstructions to slow it down, it would maintain its velocity forever and no telling where it would end up. Just My thoughts.
I am going to head your way tomorrow, not sure of the time, depends on when my wife gets up, I replied to an email I thought came from you but it was from GCGF and they said I have to answer on the site. Can you give me an address?