For those who live outside of Massachusetts (lucky you)..The state dictates what the trigger pull has to be in order to be "MASS COMPLIANT". Their way of handling gun violence is to put restrictions on the legal gun owner. Manufacturers have to submit 3 of each model they want to sell in Mass, pay thousands of dollars per gun, let them drop them from many heights and angles to see if they fire accidentally, have a round in chamber indicator and then MAYBE they will approve it. You cannot buy any new Colt, Glock, or many other weapons. Some you cannot buy new, only used and made pre 98 (Glock). SW is located in Mass, so they are probably making some hanguns ONLY Mass compliant so they don't have to make models for as many states (NY, CA, MA ) among others.

Approved Weapons Rosters - Executive Office of Public Safety