Abstract: The firearm has a rigid frame comprising a pair of vertically spaced substantially parallel hollow rods which are interconnected at their respective front and rear ends by vertical crosspieces. A barrel is mounted between the hollow rods and at the end of the barrel in the vicinity of the rearward end of the frame is a breech assembly which is interconnected to both the upper and lower rods. A shoulder support is mounted on the rear ends of the rods and positioned symmetrically with respect to the barrel. The shoulder support and other components of the firearm such as the pistol grip, front stock, rear stock and sight means are each individually and independently adjustable on the frame so as to conform to the physical characteristics of an individual shooter.