For what ever reason, S&W doesn't provide exploded views and parts lists for some of their firearms.
I'm guessing it's their fear of liability... What it boils down to is they don't really want me to have a few spare parts on hand (extractor, ejector, springs, firing pin, etc.) so if I lose one at the range I can be up and running in a few minutes. Instead, I have to send it back to them. I end up with a crummy day at the range.
I was just in the market this past month for a .22 pistol.
I went on line and looked at the M&P .22, downloaded the manual, saw there was no parts list or exploded view.
Did the same for the new Ruger SR22. Found the info. From what I've seen, most parts for Rugers can be purchased online right from the factory.
Bought the SR22. (Very,very nice .22 by the way.)
I believe that S&W is missing sales because of their policy. Their company, their policy.
My policy is to put companies who don't provide the info on the bottom of my purchase list. In the case of the 15-22, the list was so short (1) that they got the sale.
S&W has very few products where they have such superior products that a person can't get an equivalent product and better "information" support elsewhere.
Stepping off the soapbox now.