I won a Ruger SR9 at a DU fundraiser and have not had a chance to shoot it yet, but last night I inserted an empty mag and cycled the slide. The slide lock would not hold the slide open. The slide hits the lock and keeps going forward into battery. It is starting to wear a groove into the lock. It seems to me as if the magazine follower is not pushing up on the lock hard enough. What can I do to fix this?