OTs-33 Pernach - Design Details

Design Details

The OTs-33 is a selective fire blowback-operated weapon firing the 9x18mm Makarov pistol cartridge; it can use both types of 9x18mm ammunition, the standard 57-N-181S and the more powerful 57-N-181SM round. The blowback operation incorporates a feature that separates the slide and barrel as they move to the rear during recoil; there is no positive lock between the slide and barrel as in other conventional designs. As the slide and barrel separate, the spent case is ejected and the slide is then forced back to the barrel by a spring action, chambering a fresh cartridge in the process. The barrel and slide continue to the rear together in recoil for another 5 mm (0.2 in) before returning to the forward position. This feature improves the automatic fire accuracy, reduces felt recoil, and is responsible for slowing down the cyclic rate of fire, without using a sophisticated rate reducer mechanism such as the one employed in the APS pistol. This method of operation also allows the use of standard and higher power 9x18mm ammunition without using a locked breech action. To further reduce felt recoil and compensate for muzzle rise during firing, some propellant gases are diverted into a ported slide cavity that acts as a muzzle brake and compensator, deflecting the gases upward to stabilize the barrel.

The OTs-33 has a double action trigger mechanism and is hammer fired, with an exposed hammer. The safety/fire selection catch is provided on each side of the pistol at the rear of the slide and has three positions: "safe" (top setting with a single white dot), semi-automatic fire (intermediate position marked with a single red dot) and fully automatic mode (lower setting with three red dots). The safety/fire selection catch is provided on each side of the pistol at the rear of the slide. When the safety/selector lever is placed in the "safe" position, it safely decocks the hammer and then returns to the safe position. An ambidextrous lever is provide inside the trigger guard, in front of the trigger, and is used to disassemble the pistol for maintenance and cleaning. There Pernach also features a loaded chamber indicator.

The weapon is aimed using iron sights that consist of an adjustable rear notch and fixed forward blade. The sights have aiming inserts for improved visibility and target acquisition.

Due to the difficult recoil produced by the pistol's lightweight design and high rate of fire, aiming can be severely affected firing in fully automatic mode. This can be alleviated by the attachment of a folding metal shoulder stock screwed on to a location at the base of the pistol grip.

The OTs-33 is fed using double-column magazines with a capacity of 18 (standard) or 27 (optional) rounds. The OTs-33 frame has an integral accessory rail under the barrel for tactical lights or laser pointers. The pistol can be equipped with a sound suppressor. The OTs-33 is issued with leather holster that features two separate magazine pouches and a shoulder rig.