I've had issues with gun games before and typically it's the fish paper on the switch inside the gun has worn. Might be worth running a ground wire up inside that gun base also.

And I have to ask....did you spray any cleaners on the gun or anywhere else. I've also have that after I've cleaned a gun game with some alcohol and if it's not fully dry, I'll get a little bite.....but sounds like you really got a BITE!

Good luck trouble shooting the problem! Sure you'll figure it out.