yep-approved locks only.
http://mdsp.maryland.gov/Document Downloads/Approved Integrated Mechanical Safety Devices.pdf
http://mdsp.maryland.gov/Document Downloads/Approved Integrated Mechanical Safety Devices.pdf
I'm sure that's by design.Don't do that! Only approved bore locks are allowed for Maryland handgun sales. Buy the lock for the caliber of gun you're buying and then stick it on the shelf for the next one down the line.
Throwing it away means you're wasting money buying bore locks. My shop (2A) simply requires you bring a lock in for a new gun. I stick the locks, new in package, on top of my safe for the next purchase. Throwing them away in protest of Maryland's idiotic law just wastes your money and the bore locks are not cheap.
Matt