Abstract: A shoulder firearm is provided with a receiver-mounted collimating optical ight comprising a housing containing a hollow pivoted, reticle holder, an elongated rod of fluorescent material mounted in the forward end of the holder, an inclined first mirror which reflects light from a reticle at the rear end of the rod transversely to a half-reflecting second mirror, parallel to the first mirror, which, in turn, reflects the light back to the shooter's eye. A vertical range scale is mounted on the second mirror adjacent to the reticle image. To aim the firearm, the shooter aligns the reticle image with a distant target. The reticle is adjusted vertically for different ranges by means of a range knob mounted on the firearm near the trigger and connected by pinion and rack gears to the reticle holder, by rotating the range knob while observing the relative positions of the reticle image and range scale. The reticle includes a horizontal fiducial marker.

Abstract: .Iadd.An improved power-actuated tool having means for preventing firing if the tool is not properly aligned with the work surface. The tool housing member includes a slidably mounted firing mechanism having cocking means extending forwardly into engagement with a sensing means mounted in the barrel member for relative axial movement therewith. A first member is attached to the barrel member. A second member is mounted within the first member for relative axial movement therewith and with respect to the barrel member, and includes a portion adapted to engage the sensing means. The second member must be moved rearwardly with respect to the first member whereby the sensing means is moved rearwardly with respect to the barrel member and engages the cocking means to move the firing mechanism into the cocked position. The tool may also include an extractor mechanism mounted on the breech end of the barrel and provided with a lip portion adapted to engage the head of a cartridge positioned in the cartridge chamber.