If it's an Eastfield M916, be careful. I had one of those once and after not very many years it started giving me every foul up a pump can give. I happily got rid of it and changed to an 1100. I'm certainly not saying yours will repeat the problems I had, but be on the lookout. If it isn't, well, good luck with it!
When I was a young aux officer I had a S&W model 3000, 18" pump but I got rid of it several years ago for an 870. As I recall they were made overseas somewhere for Smith. I was never impressed with it. As I remember I had a lot of rust problems with it down here.
Jpower, Welcome to the Forum. There's numerous 12 ga. S&W shotguns. Pumps, semi-autos, doubles, trap, skeets, riot, & marine models. Tell us which one you have and the Model number, barrel length & choke(s). Ed.