Vz.58 operating mechanism

[czrob2]

All the reviews and videos I've seen of the Vz.58 make a point of mentioning how unique the action is - a short stroke piston, with a striker, and a falling block locking mechanism.  It's not just the comparisons against the AK47, but that the Vz.58 is a unicorn unto its own.  This intrigued me, so I've been trying to find another gun with the same parameters and I'm coming up short.

Short stroke gas pistons are common, as are striker fired guns (duh), but this pivoting locking block seems to be unique among select fire or automatic guns, at least from what I can find.

Is there another gun similar to a Vz.58 in any way?  I'm fascinated that ?ermák chose these particular design elements so I'm trying to learn more.

[RSR]

It's a linear hammer, not a striker (which is effectively a joint firing pin and hammer).

The Beretta 92 and 1951 use the locking block as does/did originally the Walther P38. 

China's QBZ-95 took inspiration from the VZ58's linear hammer.

There are many short stroke gas system rifles.

I don't know that linear vs rotary hammer makes much difference on a rifle. 

[czrob2]

But no one else decided to use the same locking mechanism in an automatic rifle?  That's the part that interests me.  'Just wondering why (or why not).

[RSR]

Rotary triggers are more tunable than linear hammers -- and the need for the tab being a case in point on the reliability/alignment front

The VZ58s dropping block vs rotary bolt is a bit like front vs rear lugs on a bolt action gun -- and rotary guns allow for more a compact and linear action versus a vertical one that needs vertical space to operate.

Firearm designs are a function of known technology, machining capabilities, and intended uses and parameters at time of manufacture.

[Mercs]

The Vz58 is often referred to as striker-fired.  However as RSR points out it is technically a linear hammer design in which the hammer spring acts on the linear hammer, and it utilizes a separate firing pin.

I suppose the bolt and locking design were a result of the design requirement to have the ability to load directly from stripper clips. The bolt carrier group is more reminiscent of the SKS design than the AK47.  Isn’t it essentially an evolved SKS action, with the locking block and linear hammer, instead of the tilting bolt lockup of the SKS?

It is a marvel of engineering, but I am guessing the VZ-58 action was not widely replicated in other firearms of the world due to being designed specifically for the Czech military tactics of its day


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[RSR]

The Vz58 is often referred to as striker-fired.  However as RSR points out it is technically a linear hammer design in which the hammer spring acts on the linear hammer, and it utilizes a separate firing pin.

I suppose the bolt and locking design were a result of the design requirement to have the ability to load directly from stripper clips. The bolt carrier group is more reminiscent of the SKS design than the AK47.  Isn’t it essentially an evolved SKS action, with the locking block and linear hammer, instead of the tilting bolt lockup of the SKS?

It is a marvel of engineering, but I am guessing the VZ-58 action was not widely replicated in other firearms of the world due to being designed specifically for the Czech military tactics of its day

The main point about linear hammer rather than striker is that it increases the need for one additional 922r part...

So I think SKS did have an influence.  Notice the in-battery lever in particular, which was absent from the VZ52.
https://www.youtube.com/watch?v=w_NhghFlIsM

However, the Vz52 had a forward dropping block like the SKS, and was designed after the SKS (wikipedia is wrong in calling it a tilting bolt):

*Image from here: https://www.militaryarmschannel.org/post/czechoslovakia-s-sks-the-vz-52
And notes:

Like the SKS, the vz.52 uses a dropping block that engages with two cut outs on either side of the chamber and towards the front of the magazine well. By contrast, the SKS is a bit more simple in its design as the rear of the bolt engages with a shelf behind the magazine well.

Good cutaway Vz52 pic:

From here: https://secondunited.com/2016/08/06/syrians-using-vz-52/

Arizona Response Systems also has some good photos of the Vz52 disassembled: https://www.arizonaresponsesystems.com/review-assembly-dissassembly-czech-vz52-rifle/

Lastly, the CZ-38 that never went into mainstream production also has many design elements that you can see echoed in the Vz52 -- inspiration from both this and the SKS in the Vz52:
https://www.youtube.com/watch?v=Irvh7mtRr60

[RSR]

Larry Vickers posted about the Vz58 on Saturday -- haven't read through yet, but his 2 part engagement question/shtick included "what weapon was the locking mechanism derived from"

https://www.facebook.com/LarryVickers/posts/10164391748980416

[czrob2]

Well that was timely....thanks!