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4 Aug 2014 - mkillebrew


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H&K USP - .45 ACP



The H&K USP .45 is a short recoil delayed linkless firearm in .45 ACP. The initial recoil moves the slides and barrel assembly rearwards as they are interlocked by means of a single locking lug that locks into the ejection port. As the barrel moves rearward, the angular cam on the underside of the barrel engages the angled surface on the guide rod containing a captive recoil spring, pulling the rear of the barrel down and thereby disengaging it from the slide, bringing it out of battery. Upon this same initial rearward movement of the slide, a ramp at the rear contacts the disconnect at the back of the frame which pushes down on the transfer bar, removing it from its contact surface on the sear, and disengaging the firing pin safety arm. When the slide fully recoils, the ejector that is integral to the rear of the frame impacts the casing, ejecting it from the breech face. At this point the recoil spring forces the slide forward, stripping the next round from the magazine and chambering it. The lugs on the barrel and guide rod again interact, pushing the rear of the barrel up into the ejection port, bringing the pistol into battery. When the trigger is pulled, it pivots at the top, pulling the transfer bar, that runs inside the right side of the frame, forward. The transfer bar then pulls the bottom legs of the sear and firing pin bar forward, releasing the sear from the hammer and pushing up on the firing pin block at the rear of the slide, disengaging the safety and allowing the firing pin to move forward upon impact of the hammer, starting the operating cycle over again. The USP has a safety selector allowing it to be carried in condition one, or if fully depressed, decocked and in condition two, if it's a variant one group as this one is. The frame consists of a steel skeleton encased in a lightweight polymer while the slide is steel.

Right Side:

Left Side:

Slide Locked Open - Ejection Port:

Slide Locked Open, Continued

Slide Locked Open, Continued

Slide - Above Profile:

Muzzle:

Single Locking Lug - Engaged:

Single Locking Lug - Disengaged:

Slide Removed - Underside:

Slide Removed - Underside Without Recoil Spring or Barrel:

Breech Face Showing Extractor:

Barrel, Recoil Spring, and Guide Rod Assembly:

Chamber Face:

Frame - Above:

Frame - Fire Control Group and Hammer:

Frame - Side:

Rear End of Slide:

Magazine:

Oblique: