One of the benefits I see purported of the Vz.58 is it's light weight despite a milled receiver, especially in comparison to an AK-47 or Galil (Ace).
Maybe I just want buyer's confirmation, but why is that so? Is the Vz.58 too light for its own good in regards to sturdiness? Or are the AK-47 and Galil's of the world way overbuilt? Surely all that extra weight can't be in the long-stroke piston rod?
According to this old thread, Vz58s bolt, bolt carrier, and piston weight more than AK:
https://czfirearms.us/index.php?topic=65144.0But all of that mass isn't pounding on the receiver like w/ the AK47 due to piston being separate... I don't think that alone explains why Vz58s are robust with milled receivers while AK47s and Galils have been known to crack, however...
Not sure where all the weight differences are, you'll need to check individual components. I agree w/ vblue42 that front and rear trunnions do matter. Vz58 beaverbarf is also lighter than solid wood. You also have the full length top cover on an AK (steel vs aluminum on a VZ58), a longer upper handguard tube (AK steel again vs I *think* the Vz58 might be aluminum excepting pin), etc.
The reason Vz58s are painted and Century did Vz2008s in teflon is b/c all the different metals require different coatings so don't look good w/ various parkerization, anodizing, etc., finishes. A top coating or universal coating is needed for uniformity.
So I think it's probably more an issue of use of lighter (and often stronger) materials and also not needing to double up materials layers on the Vz58. There's a lot of riveted/welded double-layer stuff on an AKM. Remember sheet metal frame was primarily for durability, to allow more give/bend before breakage in that relatively violent and crude system...