Abstract: A machine pistol with means for retarding blowback of the slide assembly. The device has both right hand and left hand stocks to enable the weapon to be fired from a comfortable visual sighting position at eye level with the wrist axes perpendicular to one another. The slide assembly includes a bolt that carries the firing pin, extractor and ejector and that reciprocates relative to the receiver and barrel, and a tubular cylindrical muzzle sleeve removably connected to the forward end of the bolt and that fits coaxially around the barrel. A coaxial helical spring fits between the barrel and muzzle sleeve to urge the muzzle sleeve (and bolt) to the forward firing position wherein the forward end of the muzzle sleeve extends outwardly beyond the end of the barrel.