Thanks for the replays people
Unfortunately the slide is in such a bad way you cant read any markings, it has holes that are ate through it, and when I did contact s&w they couldn't tell me much other then from the frame.
The barrel is 5.5 inches and I did buy a 17 rd 9mm mag and it fit like a...
This is an older model I found where the slide was so bad you could not read the markings o. It.
I know it is some sort of a sd9 or 40, but just not sure which.
The barrel is about 4.5 inches long. Any help will be helpful because I would like to rebuild it.
Thank you everyone for your help