I'm trying to fit my cobra rba on a wizards apprentice, but the 510 contact on the cobra won't reach the connection on the WA. I tried unscrewing it, but all it does is come all loose. When I screw it in with the 510 connection loose, then press on the positive post, it fires up so I know its just a connection problem. Anybody know how to adjust the 510 connection on a cobra and make it longer? Thanks all!