Does one need to use an approved lock to secure a firearm under M.G.L. c. 140, § 131K or does the firearm only need to be sold with an approved lock?
http://www.mass.gov/eopss/firearms-reg-and-laws/firearm-safety-locking-devices.html
http://www.mass.gov/eopss/firearms-reg-and-laws/firearm-safety-locking-devices.html