40 mm grenade

The 40 mm grenade is a military grenade caliber for grenade launchers in service with many armed forces. There are two main types in service: the 40×46mm, which is a low-velocity round used in hand-held grenade launchers; and the high-velocity 40×53mm, used in mounted and crew-served weapons. The cartridges are not interchangeable. Both 40 mm cartridges use what the US Army during the Vietnam War called the High-Low Propulsion System.

The less powerful 40×46mm is used in hand-held weapons such as the M79, M203, the M320 grenade launcher, and the multi-shot M32 MGL or Zakłady Mechaniczne "Tarnów" SA RGP-40.

The more powerful 40×53mm is used in automatic grenade launchers mounted on tripods, vehicles or helicopters, such as the Mk 19 grenade launcher, the Mk 47 "Striker" 40 mm Grenade Machine Guns (GMGs), the Heckler & Koch GMG or the South African Vektor Y3 AGL. In these roles, the rounds are linked together with a metallic disintegrating link.

A new 40×51mm cartridge recently (2007) developed in South Africa provides a more powerful alternative for hand-held weapons without increased recoil. A new version of the Milkor MGL chambered for the new round remains backward compatible with existing 40×46mm rounds.

Grenade launcher

A grenade launcher or grenade discharger is a weapon that launches a specially-designed grenade or a grenade cartridge with more accuracy, higher velocity, and to greater distances than a soldier could throw it by hand.

Grenade launchers can either come in the form of standalone weapons (either single-shot or repeating) or attachments mounted under the barrel of a rifle. Some rifles have been designed to fire rifle grenades, either from their muzzle or from a detachable muzzle-mounted launcher. Larger grenade launchers, such as the Mk-19, may be mounted on vehicles.

Today, most grenade launchers are man-portable, shoulder-fired weapons issued on a squad level, although larger launchers are issued at the company or battalion level. The most common grenade-round in use by NATO is the 40 mm fragmentation grenade, which is effective against a wide range of targets, including infantry and lightly armored vehicles. The large size of modern grenade launcher projectiles allows for the design of many "specialty" grenades, such as less-lethal sponge grenades and flares.

Destructive device

In the United States, a destructive device is a type of firearm or explosive device regulated by the National Firearms Act of 1934, revised by the Omnibus Crime Control and Safe Streets Act of 1968 and Gun Control Act of 1968.

Examples of destructive devices include grenades, and firearms with a bore over one half of an inch (.50 inches or 12.7mm), including some rifles and shotguns, both semi automatic and manually operated. While current federal laws allow destructive devices, some states have banned them from transfer to civilians. In states where banned, only law enforcement officers and military personnel are allowed to possess them.

All National Firearms Act firearms including destructive devices, must be registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The definition of a "destructive device" is found in 26 U.S.C. § 5845(f). The definition reads as follows:

The term "Secretary" originally referred to the Secretary of the Treasury, as the National Firearms Act is part of the Internal Revenue Code of 1986—since the BATF's transfer to the Department of Justice in 2002, the term "Secretary" now refers to the Attorney General.