The S&W Model 3000 was made for S&W by Howa of Japan.
After S&W dropped it, they were sold by Mossberg for a few years, also as the Model 3000,
After Mossberg dropped them, they were sold under the Howa name as the Model 3000.
They also made a semi-auto as the Model 1000 sold by all three.
The Model 3000 was a close copy of the Remington Model 870.
For a few years it had a cult following among cops, but very few agencies bought it, staying with the Remington 870.
Ultimately the Model 3000 didn't sell, simply not having enough to offer over the better known Remington.
The guns themselves were very nice quality and stand up well to hard use.
At one time Havlin Sales had all the parts under both S&W and Mossberg names. Possibly they still do.
Currently Gun Parts Corp has parts.