Which firearms are strictly controlled and cannot be sold by an auctioneer without the proper Federal firearms license?

The correct answer identifies machine guns, short-barreled shotguns, and short-barreled rifles as strictly controlled firearms that require a proper Federal firearms license for sale. This regulation stems from the National Firearms Act (NFA) of 1934, which was designed to regulate certain types of firearms that are considered more dangerous due to their potential for rapid fire or concealment.

Machine guns, for example, are fully automatic weapons that can fire multiple rounds with a single pull of the trigger, which greatly increases their lethality. Short-barreled shotguns and rifles also pose increased risks due to their concealable nature and versatility in use, making them subjects of tighter legal restrictions. Therefore, an auctioneer intending to sell these firearms must possess the appropriate licensing, ensuring compliance with federal legal frameworks designed to control their distribution and ownership.

In contrast, the other types of firearms mentioned in the other options, like standard shotguns, revolvers, or pistols, are generally not subject to the same stringent regulations under federal law, which allows them to be sold without the need for specialized licensing outside of standard background checks. This distinction is crucial for anyone in the auctioneering profession to understand, as it pertains to legal compliance and the protection