Patent ID: 8297176

Claim:
In a semiautomatic firearm having a firing chamber, a barrel, a frame, a slide movable with respect to the barrel and the frame between battery and full recoil positions, means for sequentially ejecting a spent cartridge and loading a fresh cartridge during each recoil cycle, and a firing mechanism for firing the cartridge when the slide is in battery, the improvement, comprising: (a) a spring tube having a rear end and a front end, and including an outer surface and a pair of opposed longitudinal slots extending from the front end to the rear end, and wherein the spring tube is slidably disposed within an opening in the slide; (b) an inner spring residing within the spring tube, wherein the inner spring includes a first spring constant; (c) an outer spring residing around the outer surface of the spring tube, wherein the outer spring includes a second spring constant, and including an annular cap connected to the front end of the outer spring; (d) a locking device disposed within the front end of the inner spring, and having opposing tabs slidably engaged within the slots of the spring tube and with the opening of the slide, and wherein the opposing tabs are biased against the front end of the slots by the annular cap of the outer spring; (e) a spring stop operatively connected to the rear end of the spring tube and engaged with the barrel, wherein the spring stop includes a rod residing coaxially within the inner spring; (f) an anti-rotation spring operatively attached between the spring tube and the spring stop, wherein the anti-rotation spring is adapted to permit partial and biased rotation of the spring tube and the locking device relative to the spring stop between a first rotational position and a second rotational position; (g) wherein the opening in the slide includes opposing recesses adapted to permit slidable passage of the opposing tabs through the opposing recesses, and to allow compression of only the outer spring, when the locking device and the spring tube are in the second rotational position for loading a first cartridge; and (h) wherein the opposing tabs are engaged by the slide, and both the inner spring and the outer spring are allowed to compress, when the locking device and the spring tube are in the first rotational position for firing the first cartridge and subsequent cartridges.