The VZ.58 is a short-stroke gas operated, striker fired rifle with a tilting locking breech block in 7.62x39. When the selector is set to fire, it allows the spring loaded trigger arm to rise and brings it into the operating plane of the sear. The sear holds back the striker that would otherwise be moved forward under power of the striker spring captive to the receiver cover. When the trigger is pulled, the arm moves forward, pulling on the bottom of the sear which pivots on its axis pin, lowering the rear end and releasing the striker. The striker itself rides on its own rail inside the receiver, through the bolt carrier, and into the bolt, striking the firing pin. When the gas enters the gas port, it propels the piston rearward and vents from the bottom of the gas block. The piston returns to its position by means of its own spring. When the bolt carrier begins its recoil, a sloped lug inside contacts the bottom of the lip of the breech block and begins to pull it up and out of the log recesses in the receiver. When the lugs fully disengage, the bolt, carrier, striker, and breech block begin recoiling as a group. The casing is ejected by the ejector that is a separate component from the receiver but staked in place. While moving rearward, the bolt carrier contacts the disconnector which is simply a vertical extension of the semi-auto trigger arm that is spring loaded, disengaging the sear from the trigger arm, which is returned to its original position by the multi-purpose spring riveted to the receiver. The leaf spring itself serves three functions; a sear spring, a detent spring for the selector, and a spring for the detent pin that locks the receiver cover pin in place. The group then starts to return to battery under power of the recoil spring attached to the receiver cover just above the striker spring. The striker is retained by the sear as the rest of the group continues to battery, stripping a round from the magazine and chambering it. When bolt is flush against the breech face the carrier continues moving forward, forcing the breech block to pivot down in front, and into the receiver recesses, again locking the action. The VZ.58 also features a bolt hold open that engages the bolt carrier when the magazine is empty and the rear of the follower contacts it through a hole in the back rib of the magazine. It can also be manually activated as it is located next to the magazine catch. To disengage it, the bolt carrier is pulled and released. Field stripping is accomplished by pulling out the detent pin on the forearm, exposing the piston that can be pushed into the receiver, tilted upwards, and removed. The receiver cover is removed in the same manner, but the rifle must be decocked first to allow the piston spring guide rod to pivot as the cover is removed. The bolt group slides out in one piece, the striker is rotated slightly to unlock from the carrier, and removed. The fire control group is either held in with e-clips in the case of most US made rifles, or a pivoting plate that locks into the grooves cut in the axis pins. This particular rifle is currently lacking both as a plate is being fabricated for this purpose.
Other resources of interest may be the Illustrated Comparison of the VZ.58 and AK-47 or the VZ.58 Build pages.
Right Side:
Left Side:
Right Side, folded:
Receiver, Right Side
Receiver, Left Side
Receiver, Bottom
Top, Bolt Closed:
Top, Bolt Open:
Bolt and Carrier Face, Locked Open:
Forearm:
Front Cover:
Cover Removed, Gas Piston Exposed:
Gas Piston and Spring:
Receiver Cover, Striker Spring on Bottom, Recoil Spring on Top:
Receiver Above - Cover Removed:
Receiver Above - Bolt Group Removed:
Receiver, Gas Piston at Rest:
Receiver, Gas Piston at Fully Rearward:
Gas Block, Note Venting Holes on Bottom:
Receiver, Lug Recesses Illustrated:
Bolt Group - Locked:
Bolt Group - Unlocked:
Bolt Group - Striker at Cocked Position:
Bolt Group - Underside:
Bolt Carrier - Underside:
Bolt and Breech Block:
Bolt:
Breech Block, Note Carrier Engagement Surface on Front:
Striker:
Cover Removed, Striker Cocked:
Cover Removed, Striker Released:
Fire Control Group, Note Disconnector Extending Upwards from Trigger Arm:
Receiver, Stripped, Leaf Spring Riveted in Place:
Leaf Spring, Rear Arm Engaging Detent Pin:
Fire Contol Group, Underside, in Functional Configuration:
Trigger Assembly:
Sear:
Selector:
Magazine Catch Left, Bolt Hold Open Right:
Follower Extending from Empty Magazine, Ready to Engage Bolt Hold Open:
Front Sight Block and Muzzle Brake:
Bayonet Lug:
Magazine:
Oblique:
