9 mm (SR9) threaded barrel source wanted

Many handgun manufacturers, or aftermarket product sellers, offer threaded barrels (allowing for suppressors) for non-Ruger semi-autos.
1. Why am I never able to find a source for same for SR9s or other Ruger semi-autos?
2. Is there a technical reason, related to Ruger designs, that prevent operation with Suppressors?

Contact Storm Lake. They are planning to produce barrels for the SR's and will put your name on the list.