M.G.L. c. 140, § 131K requires that any firearm or large capacity weapon sold within the Commonwealth must be sold with a safety device designed to prevent the discharge of such weapon by unauthorized users. The following safety/locking devices have been approved by the Colonel of the Department of State Police as complying with the provisions of M.G.L. c. 140, § 131K:

1

CCL Sesamee Gun Blok combination lock

2

Master Lock: cable key lock or trigger guard lock

3

Outer/Cease Fire trigger lock

4

Shot Lock Corp. keyed cable lock or trigger guard lock

5

Speed Release gun lock

6

Dominion group trigger lock

7

Remington trigger lock

8

Mossberg cable lock

9

American Firearms Council cable lock

10

Rocky Mountain Tool and Armory chamber-safe

11

Saf T Lock's magazine lock

12

Franzen trigger combination lock

13

Noble guard wall mount gun lock

14

Noble trigger lock

15

Noble double security cable gun lock

16

Central Specialties Trigger Lock Model 9311

17

Crown Trigger Lock

18

Miltex Inc. Trigger Lock

19

Concept Development Corp. / Law Lock key cuff trigger lock

20

Concept Development Corp. / Trigger block safety in conjunction with the Saf-T-Block combination lock

21

A. Rifkin Company Arcolock-7 keyed lock model

22

Armloc Magnum (handgun safety system) combination lock container

23

Franzen model 6.0 combination cable lock

24

Franzen keyed trigger lock

25

Concept Development Corp. Law Lok III, key cuff trigger lock

26

Bell Trigger Lock model B100KA

27

Bellock model #B300-8ka cable key lock

28

Bellock economy trigger lock model #B200-3

29

CCL Security Products model K-39 Trigger Blok (keyed)

30

CCL Security Products model CA12 Sesamee Cablelock (combination)

31

Palmer Security Products model/ series 5000, 5500, 6000, 7000, 8100, 9000, push button lock/ key systems

32

Steyer M-Series Integrated Limited Access Lock with Key

33

Armadillo Gun Trigger lock (keyed)

34

Master Lock: combination gunlock

35

Taurus International - hammer key lock

36

Mossberg Safe Systems Inc. Portable Electronic firearm safe

37

Life jacket by Mogul Company

38

Saf-T-Trigger

39

DAC Technologies Items: MTL, LHL, TVP, GL001, CL200, CL100

40

UNEX Keyed trigger lock and keyed cable lock

41

Alarm It w/cable lock

42

Smart Trigger lock with alarm

43

Maximum security cable lock

44

Regal keyed cable lock model SL14-4PTACA

45

Project HomeSafe Cable Lock

46

Omega Safety Systems Internal Chamber Lock

47

Project Child Safe Cable Lock w/Key

48

Regal keyed cable lock model DCSC-5-DTACA14

49

VisualLock (special Keyed lock)

50

CABLE LOCK (NAD Corporation, Worcester, MA)

51

CHILD GUARD (Child Guard LLC, Lancaster, PA)

52

Regal Industrial Sales, 

Models R11SC3, R14CBS3, R15SCA, R15SC3, R15SC3-01, R15LC1, R15LC3, R38LASC3, R38LASC3-NC, R38LALC3, R60SC3, R60LC3, RTL06, M2006, M2007J

53

Firearms Safety Devices Corporation, 

Models FSDC CL1010BKD, CL1020RKD, CL1335BKD, CL1335RKD, CL1070BKD, CL1070RKD, CL1095BKD, CL1095RKD, CL1145BKD, CL1145RKD, CL1250BKD, CL1250RKD, CL1335BKD, CL1335RKD, CL1560RKA, CL1725RCB, CL1850BKD, CL1850RKD, TL3110BKD, TL3120RKD, TL3510RKA, TL3180RCB, TL3325BCB, TL3845RCB, TL3730BKD, TL3760RKD, TL3770RKA, FSDC-CL1725BCB,  FSDC-TL3030BKD, FSDC-TL3060BKA

54

Trimax Locks

Models TGCL44 and TGL22

(List Revised 6-1-2016)
This list will be supplemented periodically

In addition to the approved list, pursuant to the provisions of M.G.L. c. 140, the Colonel of the Department of State Police has determined that locks provided by the manufacturer of firearms, or large capacity weapons, both as defined in Section 121 of Chapter 140, sold within the Commonwealth, that are designed to prevent the discharge of such weapon by unauthorized users shall be deemed as approved locks for the purpose of complying with the provisions of M.G.L. c.140, § 131K.

M.G.L. c. 140, §131K states that all sales of firearms and large capacity weapons in Massachusetts MUST include a safety device approved by the colonel of state police. This requirement applies to any seller including a wholesaler. The seller is not required to install the device so long as the weapon is accompanied by it. Failure to comply with this provision will constitute a breach of warranty and an unfair trade practice. This section does not apply to non-large capacity rifles and shotguns. Sellers should ensure that the safety device is appropriate for the weapon being sold. 

Responsible firearms owners must recognize the need and be aware of the methods of securing and childproofing their firearms, whether or not they have children.  Not all gunlocks work on all guns and no lock is appropriate for all of the different types of firearms that exist.  Owners must make sure that their locks are appropriate for the gun it is used with.  Please make every effort to ensure that locks fit properly and make the gun mechanically inoperable, and test the fit and functionality of the lock.  Trigger locks often come into direct contact with the trigger and should never be installed on loaded guns.  In addition, it is strongly recommended that firearms owners store all guns unloaded, and store the ammunition separately.