Back to the main page An Illustrative Comparison of the VZ-58 and AK-47 The similarities and interchangable parts are as follows. The 7.62x39 or M43 intermediate round; nothing else is interchangable at the least, and radically conceptually deviant at most. The audience of this is not just the lay person that sees the external resemblance, but those more familiar with firearms in search of an explaination the functionality of each. AK-47 http://50ae.net/vz-vs-ak/ (1 of 36)21.4.2011 21:22:37
To sum up the operating principles of the AK-47 as concisely as possible, it's a automatic firearm whos exhaust gasses are tapped from the barrel moving a gas piston affixed to the bolt carrier rearward, rotating a two-lug bolt that locks to the front trunion in which the barrel is pressed into thereby unlocking the bolt which continues rearward with the carrier, cocking the hammer before it reverses its movement, strips a new round from the magazine and locks back into battery. VZ-58 http://50ae.net/vz-vs-ak/ (2 of 36)21.4.2011 21:22:37
In retrospect, the VZ-58 is an automatic firearm whos exhaust gasses are tapped from the barrel which act on a gas piston not attached to the bolt carrier which moves rearward and acts upon the bolt carrier to move it rearward. While the piston returns to its original position recessed inside the gas block, a wedge in the VZ-58's bolt carrier lifts the locking breech block out of the recesses in the receiver. The locking breech block pivots on its rear on the bolt. The bolt itself does not tilt and instead moves directly rearward. In the rearward movement the bolt carrier impacts the disconnector and cocks the striker which operates on a seperate spring from the bolt group spring. Illustrative Comparison: I. Locking Bolt Groups: http://50ae.net/vz-vs-ak/ (3 of 36)21.4.2011 21:22:37
VZ-58 bolt group with breech block in locked position. AK-47 bolt group in locked position. Bolt Groups, continued: VZ-58 bolt group with breech block in unlocked position. AK-47 bolt group in unlocked position. Bolt Carriers: http://50ae.net/vz-vs-ak/ (4 of 36)21.4.2011 21:22:37
Left: VZ-58 bolt carrier. Right: AK-47 bolt carrier. Means of unlocking: http://50ae.net/vz-vs-ak/ (5 of 36)21.4.2011 21:22:37
Left: VZ-58 wedge inside carrier that lifts breech block. Right: AK-47 recesses that rotate bolt. Bolt: Left: VZ-58 bolt with locking breech block. Right: AK-47 bolt; notice two locking lugs. Breech Block: http://50ae.net/vz-vs-ak/ (6 of 36)21.4.2011 21:22:37
Image: VZ-58 breech block, the AK-47 has no comparable component. Locking Recesses: http://50ae.net/vz-vs-ak/ (7 of 36)21.4.2011 21:22:37
Left: VZ-58 locking recesses in receiver rail. Right: AK-47 locking recesses in front trunion. As evidenced in the pictures, the VZ-58 locks by means of a dropping locking breech block while the AK-47 locks by means of a rotating locking bolt. II. Gas System Gas Block: http://50ae.net/vz-vs-ak/ (8 of 36)21.4.2011 21:22:37
Left: VZ-58 gas block. Right: AK-47 gas block. Gas Piston: Left: VZ-58 gas piston removed, complete with return spring. Right: AK-47 gas piston removed, attached to bolt carrier. Gas Piston, continued http://50ae.net/vz-vs-ak/ (9 of 36)21.4.2011 21:22:37
Left: VZ-58 gas piston in place, top foregrip removed. Right: AK-47 gas piston in place, top foregrip removed. As illustrated, the gas system on the VZ-58 is a short-stroke as the piston returns to its initial position while the bolt group continues rearward. The AK-47 is a long-stroke as the gas piston is attached to the bolt carrier and therefore must follow the bolt group through its entire cycle. III. Fire Control Group Firing Pin Striker: http://50ae.net/vz-vs-ak/ (10 of 36)21.4.2011 21:22:37
Left: VZ-58 cylindrical striker. Right: AK-47 hammer. Striker/Hammer Spring: Left: VZ-58 Striker spring, attached to receiver cover and positioned directly below bolt spring. Sear: Right: AK-47 hammer spring, wraped around hammer crosspin http://50ae.net/vz-vs-ak/ (11 of 36)21.4.2011 21:22:37
Left: VZ-58 modified sear to act as semi-auto only with striker cocked. Right: AK-47 sear attached to trigger with hammer cocked. Sear, continued: http://50ae.net/vz-vs-ak/ (12 of 36)21.4.2011 21:22:37
Left: VZ-58 modified sear without striker cocked. Right: AK-47 sear without hammer cocked. Sear, continued 2: http://50ae.net/vz-vs-ak/ (13 of 36)21.4.2011 21:22:37
Left: VZ-58 sear spring, also acts as detent spring for safety and detent spring for top cover retaining pin. Disconnector: Right: AK-47 trigger spring ends rests on trigger/sear assembly acting as a sear spring. http://50ae.net/vz-vs-ak/ (14 of 36)21.4.2011 21:22:37
Left: VZ-58 disconnector which disengages the sear from the trigger when struck by bolt carrier. Disconnector, continued: Right: AK-47 disconnector attached to trigger group. http://50ae.net/vz-vs-ak/ (15 of 36)21.4.2011 21:22:37
Left: VZ-58 disconnector spring integral to the trigger group. Right: AK-47 disconnector spring situated below disconnector resting on trigger/sear component. Safety: http://50ae.net/vz-vs-ak/ (16 of 36)21.4.2011 21:22:37
Left: VZ-58 safety, acts upon trigger arms to clear or engage from sear. safety on. Right: AK-47 safety, acts upon arms of trigger component to restrict movement. safety on. Safety, continued: http://50ae.net/vz-vs-ak/ (17 of 36)21.4.2011 21:22:37
Left: VZ-58 safety disengaged. Right: AK-47 safety disengaged. Safety, continued: Left: VZ-58 safety, external. Right: AK-47 safety, external. > > http://50ae.net/vz-vs-ak/ (18 of 36)21.4.2011 21:22:37
The trigger assembly of the VZ-58 deserves more attention to adequately explain its method of operation. The trigger pivots on crosspin driven through the receiver, thereby pulling the trigger arms hinged on its top foreward. A projection on the semi-auto trigger arm acts on the bottom of the sear pulling it foreward, which in turn pulls the rear of the sear where the striker rests down, thereby releasing the striker. Left: VZ-58 trigger assembly removed. Right: AK-47 trigger assembly removed. http://50ae.net/vz-vs-ak/ (19 of 36)21.4.2011 21:22:37
Left: VZ-58 trigger at rest. Right: VZ-58 trigger pulled. The disconnecting function is also built into this trigger assembly. When the bolt carrier moves rearward it impacts the disconnector arm which is connected directly to the semiauto trigger arm. This action moves the trigger arm downward to disengage the sear which then returns to its original position under power of the sear spring. This functions in much the same way the safety does, to lower the trigger arm so it cannot engage the sear, but only temporarily. http://50ae.net/vz-vs-ak/ (20 of 36)21.4.2011 21:22:37