In short:
http://www.fsguns.com/regulations.html
This page contains the approved roster:
http://www.state.ma.us/chsb/frb/frb.html
But you can't actually fucking buy anything even if it's on the roster because
http://www.mass.gov/legis/laws/seslaw98/sl980180.htm
It has to be approved by our ass of an attourney general. Every manufacturer must submit two samples of every gun for testing to get it approved by the AG. The samples are destroyed.
Summary of the Attorney General 940 CMR 16.00 et seq. regulations
_ The regulation is a manufacturing specification that requires at least the following:_
Performance Test__________ Limits of Accuracy Test ____________ Metalurgical Test_
Drop Test ________________________ 10 lb Trigger Pull _____________________ Hidden Serial Number_
Loaded Round Indicator or Magazine Disconnect ____________ Detailed Safety Briefing and Disclosures_
Approved Lock (from Dealer)_