Insurgency weapons and tactics are weapons and tactics, most often involving firearms or explosive devices, intended for use by insurgents to engage in guerrilla warfare against an occupier, or for use by rebels against an established government. One type of insurgency weapon are "homemade" firearms made by non-professionals, such as the Błyskawica (Lightning) submachine gun produced in underground workshops by the Polish resistance movement. Another weapon that is part of the conventional military arsenal, but which has been taken up to great effect by insurgents, is the RPG. Two examples of an improvised weapon used by insurgents would be the improvised explosive devices used in Iraq and the Molotov cocktails (glass bottles filled with gasoline) used against vehicles and tanks. Two tactics used by many insurgents are assassinations and suicide bomb attacks. The latter tactic is used when an insurgent has a bomb strapped to them or in their car, which provides a low-tech way for insurgents to get explosives close to critical enemy targets. Purpose-designed weapons A fairly recent class of firearms, purpose-designed insurgency weapons first appeared during World War II, in the form of such arms as the FP-45 Liberator and the Sten submachine gun. Designed to be inexpensive, since they were to be airdropped or smuggled behind enemy lines, insurgency weapons were designed for use by guerrilla and insurgent groups. Most insurgency weapons are of simple design, typically made of sheet steel stampings, which are then folded into shape and welded. Tubular steel in standard sizes is also used when possible, and barrels (one of the few firearm parts that require fine tolerances and high strength) may be rifled (like the Sten) or left smoothbore (like the FP-45). The CIA Deer gun of the 1960s was similar to the Liberator, but used an aluminum casting for the body of the pistol, and was chambered in 9×19 mm Parabellum, one of the all-time most common handgun cartridges in the world. There is no known explanation for the name "Deer Gun", but the Deer Gun was intended to be smuggled into Vietnam, attested by the instruction sheet printed in Vietnamese. It was produced by the American Machine & Foundry Co., but was a sanitized weapon, meaning it lacked any marking identifying manufacturer or user. Details of the manufacture of insurgency weapons are almost always deliberately obscured by the governments making them, as in the designation of the FP-45 pistol.