In that MA likes to think of itself as California East, here is the CA DOJ requirement (note at the end that a UL RSC-rated safe is acceptable):
An acceptable gun safe is either one the following:
- A gun safe that meets all of the following standards:
- Shall be able to fully contain firearms and provide for their secure storage.
- Shall have a locking system consisting of at minimum a mechanical or electronic combination lock. The mechanical or electronic combination lock utilized by the safe shall have at least 10,000 possible combinations consisting of a minimum three numbers, letters, or symbols. The lock shall be protected by a case hardened (Rc 60+) drill resistant steel plate, or drill resistant material of equivalent strength.
- Boltwork shall consist of a minimum of three steel locking bolts of at least 1/2-inch thickness that intrude from the door of the safe into the body of the safe or from the body of the safe into the door of the safe, which are operated by a separate handle and secured by the lock.
- A gun safe shall be capable of repeated use. The exterior walls shall be constructed of a minimum 12-gauge thick steel for a single walled safe, or the sum of the steel walls shall add up to at least 0.100 inches for safes with two walls. Doors shall be constructed of a minimum one layer of 7-gauge steel plate reinforced construction or at least two layers of a minimum 12-gauge steel compound construction.
- Door hinges shall be protected to prevent the removal of the door. Protective features include, but are not limited to: hinges not exposed to the outside, interlocking door designs, dead bars, jeweler's lugs and active or inactive locking bolts.
- A gun safe that is able to fully contain firearms and provide for their secure storage, and is certified to/listed as meeting Underwriters Laboratories Residential Security Container rating standards by a Nationally Recognized Testing Laboratory (NRTL).
Well I would have to toss my 4 gun safes in that case. Combinations require letters, not just numbers? Absurd.