There are a variety of different statutory definitions of assault weapon in local, state, and federal laws in the United States that define them by a set of characteristics they possess. Using lists of physical features or specific firearms in defining assault weapons in the US was first codified by the language defining semi-automatic rifles with certain characteristics in the 1994 Federal Assault Weapons Ban. See the U.S. Code of 2004 section on firearms.
In United States military parlance an assault weapon refers to weapons designed for and used in assault operations. Current examples include the SMAW and SRAW used to breach obstacles or destroy structures. Historical examples include the Bangalore torpedo, the APOBS, and even the flame thrower. Assault rifles and shotguns capable of fully automatic fire, such as the Heckler & Koch CAWS, the XM8, and the Russian 7.62mm/40mm Assault Weapon System are also classified as assault weapon systems. This definition differs from the current variety of legal definitions used in the United States of America.
Recently terminology variants such as "Semi-Automatic Assault Weapon" and "Semi-Automatic Assault Rifle have been gaining in use by political leaders and groups who seek to limit or ban these firearms. These terms are being used to add some clarity to the term assault weapon which indicates a fully automatic firearm when applied to small arms in the military.
The close similarity to the term assault rifle and wide variety of definitions has led to considerable confusion over this term. In addition, inaccurate media reporting and political propaganda have created a common public misconception that this term covers many items regulated in the United States by the National Firearms Act (NFA) of 1934. For instance, a "grenade launcher" is listed as a classifying characteristic in many of the assault weapons laws. This frequently creates confusion between grenade launchers, such as the M203 that the general public is familiar with seeing in video games and in the media used by soldiers, and the actual classifying feature being described, which is a muzzle grenade launcher--an adapter or muzzle device that allows the launching of rifle grenades. While barreled grenade launchers such as the M203, the Russian GP-30, and the HK69 are strictly regulated as Destructive Devices under federal law by the NFA, rifle grenade launchers and other muzzle device launchers are only regulated in a handful of areas by state or local laws (such as California and New York City). Furthermore, regardless of the launcher's regulatory status, each individual grenade, both cartridge types such as the 40mm grenades used in the M203 and rifle grenades such as the WWII-era M9A1, are already strictly controlled, registered, and taxed as a Destructive Device under the NFA. Consequently, because of their status as Destructive Devices, all grenades as well as barreled launchers such as the M203 are prohibited by state laws in several states. The complex technical and legal distinctions are not commonly known, and frequently lead to misrepresentation in the media of what is actually being described. The Seattle Times made one such error during their reporting of the investigation of the DC sniper, in an article discussing the Bushmaster rifle used in the shootings and what aspects of the then-soon to expire 1994 Assault Weapons Ban might have applied to it or prohibited it (the article concluded that the XM-15 rifle used was not prohibited or affected by the ban). In a sidebar image illustrating different classifying features that were restricted by the Assault Weapon Ban, an image of a M4A1 carbine with a mounted underbarrel M203 grenade launcher was depicted; the M203 was incorrectly described as the type of "grenade launcher" feature restricted by the ban. No statement of error or correction about the misrepresentation was subsequently made.
Perhaps the largest area of confusion surrounding this term is the difference between a machine-gun, assault rifle and an assault weapon (non-military definition). A machine-gun is universally recognized as a fully automatic weapon, while the current statutory definitions for assault weapons describe them as semi-automatic. A key concept in defining the military assault rifle is the ability to provide a large volume of fire through fully-automatic or burst fire modes. Every nation that uses the term assault rifle refers to a rifle with said capability. A semi-automatic rifle does not have the capability to lay down large volumes of fire required for modern military assault operations and has not been defined as an assault rifle by any nation. The term assault weapon is more encompassing and fluid than the term assault rifle and leads to confusion that these semi-automatic weapons are fully automatic or would be used by militaries in assault operations. Further, the National Firearms Act of 1934 specifically addresses fully automatic weapons, and the private ownership and usage of them is extremely regulated. To add to the confusion, the media often refers to these semi-automatic rifles as military-style assault weapons. Military assault rifles are also designated under the heading of assault weapon systems by several countries but are capable of full automatic fire creating more confusion.
There is also the perception that firearms that fall under this category can be easily modified for fully automatic fire. This is not the case since the U.S. Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) regulations for manufacturers place certain restrictions on firearm product design to comply with the provisions of the National Firearms Act (NFA) of 1934 and the amendments to the McClure-Volkmer Act of 1986 that pertain to machine-gun ownership. These regulations require that semi-automatic firearms sold in the United States be especially difficult to convert to fully automatic operation.
The use of the term assault weapon and its similar appearance to military rifles has led to a misconception that they are more dangerous or powerful than other semi-automatic firearms. In fact, the rifles designated assault weapon are most often small caliber and would be used only for small game such as rabbits or prairie dogs by hunters. Some states ban the use of the most common chambering, .223 Remington / 5.56 x 45 mm NATO, for hunting deer as it is underpowered for that purpose.
There are a wide variety of opinions concerning the appropriateness of legislative attempts to ban assault weapons and the suitability of these weapons for private ownership. This section merely attempts to provide the reader with some of the more widely held viewpoints for further consideration.
Those who support legislative attempts to ban guns, including but not limited to groups such as the Brady Campaign and the Coalition to Stop Gun Violence, are highly critical of the private ownership of these weapons. They hold that assault weapons are designed to maximize lethal effects through a rapid rate of fire and by being spray-fired from the hip. They further contend that because of their design, a shooter can maintain control of an assault weapon even while firing many rounds in rapid succession, and thus, assault weapons pose an especially serious threat to public safety and should be banned. They also believe that all Americans have the right to be safe from gun violence; the availability and lethality of guns, and especially assault weapons, make death or severe injury more likely in domestic violence, criminal activity, suicide attempts, and unintentional shootings; and that it is possible to reduce the number of deaths and injuries caused by gun violence in general with reasonable, common sense policy, but especially through banning assault weapons. Many who oppose weapons of all kinds, but especially assault weapons, contend that there is no need in modern society for weapons, and that weapons only serve to escalate hostile situations, such as in hostage-taking or spree killings.
Those who oppose attempts to ban "assault weapons", including groups such as the National Rifle Association and Gun Owners of America, hold that the statutory laws defining "assault weapons" describe cosmetic appearances, only. As such, the operating characteristics of, and the firepower of these weapons is not significantly different from many other firearms having a different appearance. To bolster this argument, it is often pointed out that many weapons commonly classified as "assault weapons", such as semi-automatic versions of military assault rifles, use smaller calibers and less-powerful ammunition than many legal hunting rifles. They also suggest that these weapons are generally suitable for target shooting, collecting, and when necessary, civil and self defense (for example, to defend life and property during civil disturbances and emergencies when law enforcement services are not available, as evidenced in their successful usage by Korean-American store owners during the 1992 Los Angeles riots). They further contend that these types of weapons are not frequently used in crime, as evidenced by US Department of Justice statistics. Authors supporting gun rights such as Kenneth W. Royce additionally counter the "rapid rate of fire and spray-fired from the hip" beliefs by stating that rapid rates of fire do not necessarily increase the lethal effects of weapons, but all too often serve only to "convert money into noise" at a more rapid rate. The end result, according to such authors, is that "assault weapons" only pose an apparent threat to public safety through their appearance, and banning them is for purely political reasons, and not for increasing public safety. Many who oppose attempts to ban assault weapons also assert that the right of Americans to possess them is guaranteed by the Second Amendment. The Supreme Court case United States v. Miller held that, in fact, the purpose of the Second Amendment is specifically to protect civilian ownership of weapons suitable for military use.
Women's groups, such as Second Amendment Sisters and Women Against Gun Control, do not support any legislation or policy that limits the rights guaranteed by the Second Amendment. They consider self defense to be a basic human right, since U.S. citizens are guaranteed the right to life and therefore have the right to protect that life. They advocate for women and others whose only reasonable means of self defense is a firearm. Many of the features the anti-gun groups seek to use to define "assault weapons" are the very features that make these firearms usable and safe for this population.