The United States Code in reference to the term "short-barreled shotgun" means a shotgun that has one or more barrels less than eighteen inches (18") in length, and any weapon made from a shotgun (whether by alteration, modification, or otherwise) if such a weapon as modified has an overall length of less than twenty-six inches (26").

Source

18 USC § 921(a)(6)

DOES THAT MEAN THAT THEY ARE ILLEGAL?

It's complicated. The best way that I can explain it to you is to start at the beginning. Let's start with the NFA. Always be aware of your local and state laws. The NFA sets a national standard. In several states, state laws are more defined and even more strict than those listed in the NFA. For the most part, it is legal to purchase a shotgun if you are at least 18 years old or older and are in good legal standing with your state. There are still other laws that apply not only for shotguns but for most guns state by state. For this simple categorization, we are talking about a shotgun purchase that lies within the legal measurements defined above - 26" overall / 18" barrel, a regulation, and legal shotgun purchase.

WHAT ATF HAS TO SAY ABOUT SHOTGUNS

Most of the shotguns made and sold in America are considered to be for sporting uses; hunting and home defense included. The majority of shotguns manufactured here have an overall length of 26" or more and a barrel 18" or longer. Shotguns like this are not restricted by NFA regulations, as they are designed and manufactured to a predetermined legal standard. A couple of other legal shotgun features to keep in mind are that they are designed to be fired from the shoulder, and it uses energy from a shotshell; ball, or slug to propel several projectiles or one projectile down a smoothbore with each pull of the trigger. The devil is in the details, and ATF has several definitions for various shotgun or shotgun style firearms. Remember, once a shotgun no longer reaches the legal standards in measurements set forth by the NFA, it becomes subject to NFA regulations and taxation.

NFA REGULATIONS

Believe it or not, short barrel shotguns are still not illegal to purchase if you follow the NFA guidelines. For SHORT BARREL SHOTGUNS - To purchase a shotgun with a barrel under 18" long, you simply fill out specific paperwork and submit it, get the approval to transfer the SBS to your ownership, and pay a $200 fee for an NFA tax stamp. There is an ATF firearm typing guide that outlines the types of firearms that fit into one of several categories. For a firearm that does not specifically fit into a defined category, there is a catch-all term and definition. The categorization is appropriately named All Other Weapons, or AOW for short. "Any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive, a pistol or revolver having a barrel with a smoothbore designed or redesigned to fire a fixed shotgun shell, weapons with combination shotgun and rifle barrels 12 inches or more, less than 18 inches in length, from which only a single discharge can be made from either barrel without manual reloading, and shall include any such weapon which may be readily restored to fire. Such term shall not include a pistol or a revolver having a rifled bore, or rifled bores, or weapons designed, made, or intended to be fired from the shoulder and not capable of firing fixed ammunition." Any Other Weapon means any short-barreled, smoothbore guns that were originally manufactured to be fired from one hand (and not from the shoulder) as well as some fairly exotic weapons that combine rifle and shotgun barrels in a compact design. A $200 NFA tax stamp to manufacture, plus a $5 NFA tax stamp, along with paperwork, to transfer. (Source: Shooting Illustrated). There are many other regulations, but as far as Short Barrel Shotguns go, the aforementioned shotgun-style firearms are where we are going to focus.

Mossberg Shockwave

EVERYTHING THAT GLITTERS

Everything that glitters is not gold, and everything that fires a shotshell is not a shotgun. It's true! Let's take the most well-known of these firearms; the Mossberg Shockwave. Firearms like this one and others similar can legally have a 14" barrel with a 26" overall measurement and not fall under NFA shotgun regulations, and therefore do not need a tax stamp. Firearms like this are not considered shotguns. Shotguns require a stock, and are designed to be shoulder-fired. Firearms that were not designed to be shoulder-fired even though they fire shotshells are categorized as simply "firearms", some states even consider them rifles. So the loophole with these types of firearms is that they can be purchased with the same paperwork that you would be required to fill out for any other firearm purchase, the standard background check, and the usual 4473 ATF Form.

Kalashnikov USA Komrad

THE SNAG

Be sure to remember what the basic definition for use is when owning one of these firearms. The very definition of a shotgun says that a shotgun is to be used for sporting purposes. If the owner of one of the legally purchased and tax stamped or legally purchased shotgun-style firearms is used in any other capacity other than sporting usage, the very definition of its legality can change. Buyers beware, if you have any nefarious ideas, you will be looking at some serious federal charges. Be legal, be responsible, and be aware of NFA, ATF, state, and local laws, rules, and regulations. Shop All Shotguns