One of my friends whom owns a gun-shop in RI recently applied for his annual MA non-res LTC, and was informed that unless you have a good reason to carry, non-res LTC's may start coming out restricted.
In the gun shops we would just put NA in the space provided. In the event that you are contacted (which won't happen) just explain that the gun is pre 68 when serial numbers were not mandatory per federal law. Stupid FA10 forms........
Not saying your wrong, but can you show me the citation stating the 21 age requirement? Also, what if you own a rifle that shoots a handgun cartridge. I know of many lever-guns that shoot .357 Magnum, .45 Long Colt, etc.
Zero Hour Arms does not sell guns that are not in compliance wit the assault weapons ban to civilians. We have many on display that have the evil features but they are neutered to be in compliant with the MA AWB before they leave the shop.