Patent ID: 8087344

Claim:
A recoil operating pistol comprising: a barrel having an internal surface adapted for discharging a projectile from the pistol and four pairs of flat external surfaces extending along a substantial length of the barrel with each in the pair being parallel to each other, one surface in the pair of surfaces being opposite to the other of the surface in the pair of surfaces on a diametrically opposite side of the barrel, and each of the surfaces being parallel to a longitudinal centerline of the barrel; a slide having a generally hollow interior adapted to receive at least a portion of the barrel, the slide hollow interior having flat internal surfaces extending along a substantial length of the slide hollow interior parallel parallel to a longitudinal centerline of the slide, the slide flat internal surfaces being arranged and having dimensions matching the pairs of barrel flat external surfaces in a manner to allow relative sliding motion between the slide and the barrel when the at least a portion of the barrel is received in the hollow interior of the slide; wherein the barrel and slide are locked together when the pistol is in battery and the barrel is movable relative to a body of the pistol when the pistol is out of battery.