After 15 years of service your Mossberg has probably got some worn parts. If so you will need to get parts for it. Chances are a gunsmith will either have them or have a source to get them.Is this Mossberg still in production?I looked it up in Gun Trader's guide and don't see that model listed.If it was mine I would take it to a smith and have throughly gone through. Ruger Redhawk