there use to in the old days
have a company that made rubber cup seals and pins...I still holding one to the one set i have....to the op if you think yours is leaking try using some very fine sand paper..if it a burr on the plastic. if it a leak...check that your not missing the star guild and the spring is going in the right way.also over tighting the valve nut can warp the valve or you put the valve in backwards. the last thing to look is the main spring is it cut to short or did it go soft and the psi going into the gun..if the psi is to low the valve wont close.
Does an ursine quadruped void wastes in an arboreal environment?