A gas pistol is a non-lethal weapon for self-defense. It is typically a close-to-exact replica or conversion of a real handgun made to be able to fire lachrymatory gas cartridges only. Effective range is up to 4,5 metres depending caliber. For legal purposes various techniques are used during manufacture/conversion to prevent the use of live ammunition, such as using calibers exclusive to gas cartridges, welding obstacles into a non-removable barrel and using mellable metal alloys. Gas pistols are prevalent in European countries with strict gun control laws. Other uses include starting pistol, flare gun, movie prop and weapons training.
Most popular calibers are the 9 mm Knall (9x17 mm R K, 9 mm R K, .380 Knall) for revolvers and the 9 mm PAK (9x22 mm) for semi-automatic. Other types include the .315 Knall, 8 mm Knall (8x20 mm), .22 Lang Knall, .45 Short Knall (.45 Knall) and the 6 mm percussion cap, loaded with 20–120 mg of CN gas, CS gas, CR gas (available only in Russia), OC (pepper) agents, or blanks.