Keeping it Traveller, it was a jump of 1-2 Law Levels regarding firearms in a single act of government. If you want to avoid "Yanks in Space" IYTU, understanding when and how the familiar norm came about reveals non-'Yanks" alternatives.
There is the even more restrictive Australian model adopted in 1996, from Wikileaks article:
A person must have a firearm licence to possess or use a firearm. Licence holders must demonstrate a "genuine reason" (which does not include self-defence) for holding a firearm licence and must not be a "prohibited person". All firearms must be registered by serial number to the owner, who must also hold a firearms licence.
The National Firearm Agreement defines categories of firearms, with different levels of control for each, as follows:.
Category A
Rimfire rifles (not semi-automatic), shotguns (not pump-action or semi-automatic), air rifles including semi-automatic, and paintball guns.
Category B
Centrefire rifles including bolt action, pump action and lever action (not semi-automatic) and muzzleloading firearms made after 1 January 1901.
Category C
Pump-action or self-loading shotguns having a magazine capacity of 5 or fewer rounds and semi-automatic rimfire rifles up to 10 rounds. Primary producers, farm workers, firearm dealers, firearm safety officers, collectors and clay target shooters can own functional Category C firearms.
Category D
All self-loading centrefire rifles, pump-action or self-loading shotguns that have a magazine capacity of more than 5 rounds, semi-automatic rimfire rifles over 10 rounds, are restricted to government agencies, occupational shooters and primary producers.
Category H
Handguns including air pistols and deactivated handguns. This class is available to target shooters and certain security guards whose job requires possession of a firearm. To be eligible for a Category H firearm, a target shooter must serve a probationary period of 6 months using club handguns, after which they may apply for a permit. A minimum number of matches yearly to retain each category of handgun and be a paid-up member of an approved pistol club.[15] Target shooters are limited to handguns of .38 or 9mm calibre or less and magazines may hold a maximum of 10 rounds. Participants in certain "approved" pistol competitions may acquire handguns up to .45 calibre, currently Single Action Shooting and Metallic Silhouette. IPSC shooting is approved for 9mm/.38/.357 SIG, handguns that meet the IPSC rules, larger calibres such as .45 were approved for IPSC handgun shooting contests in Australia in 2014, however only in Victoria so far.[16] Barrels must be at least 100mm (3.94") long for revolvers, and 120mm (4.72") for semi-automatic pistols unless the pistols are clearly ISSF target pistols; magazines are restricted to 10 rounds.
Category R/E
Restricted weapons include military weapons such as machine guns, rocket launchers, full automatic self loading rifles, flame-throwers and anti-tank guns.
Certain antique firearms (generally muzzle loading black powder flintlock firearms manufactured before 1 January 1901) can in some states be legally held without a licence.[17] In other states they are subject to the same requirements as modern firearms.