It was a blowback design in which the weight of the slide and tension of the recoil spring held the breech closed until the bullet had exited the barrel. In 1900, the Belgian firm of Fabrique Nationale (FN) had introduced the Pistolet Automatique Browning Mle. But while Searle's system apparently worked, the breech opened much faster and more violently than that of the Colt/Browning system. In an attempt to retard barrel rotation and further delay breech opening, the Model 1907's barrel was rifled so that the bullet spun in a clockwise direction, which, theoretically, counteracted barrel movement. As the breechblock went into battery, the section of helical groove inside the slide bore on the barrel lug, rotated the barrel to the left, and locked the barrel and breechblock together. A recoil spring located around the barrel pulled the breechblock forward, stripped the next round out of the magazine, and chambered it. As the bottom lug prevented the barrel from moving to the rear to any degree, the helical groove in the slide rotated the barrel to the right approximately 5 degrees where the lug entered a straight groove in the slide and allowed the breechblock to recoil fully, extracting the spent cartridge case.Īs the slide reciprocated, the cocking lever was forced upward as the rear end of the breechblock-to which the lever was pivoted-slid over the rear of the receiver and drew back the striker and engaged it to the sear. At the instant of firing, the barrel and breechblock/slide unit were locked together, but as the slide started rearward, it bore against the top lug. The barrel had a lug on top of the chamber that mated with a helical groove on the inside of the slide and another on the bottom that fitted into a slot in the frame.

Searle's design consisted of a separate breechblock that contained a spring-loaded striker with a prominent cocking lever that was inserted into the rear of the pistol's slide where it was held in place by a tongue-and-groove system.

Savage 1917 380