Finially got a chance to play with my new Air Arms .17 sporter today. Got it sighted in, fired about 60 more shots and then attempted to air it up from my tank. The supplied manual says to "place" the brass female connector completely down over the male and twist to lock. NO GO! It hits the 2nd o ring and stops. All the "placing" I can muster won't move that sucker any farther down. Am I doing something wrong?