I see that VZ58USA is selling a "Bleed piston" for use with silencers.
https://www.vz58usa.com/product/vz-58-bleed-piston/
That smaller hole is extremely sloppy... Can't get a good look at front one, but definitely a modification to existing -- from photos, it appears that they might rechrome after, but uncertain if they actually do so as I can't tell if ledge is just chrome chipping or chipped chrome w/ add'l chrome added to original after the mod. And I'm really surprised they didn't incorporate a set screw into that setup to control bleed to their new "vent hole" as another "feature"... That'd definitely make more sense IMO... But yeah, may not want to be running a top rail mount red dot with that setup -- looks a fair bit hotter than standard.
Do you think I might benefit from one of these? Would it hurt? Would it work when the silencer is not attached?
The Vz58's short stroke piston system naturally bleeds off excess pressure once the piston travels rearward enough to exit most of the gas block's piston cup.
And while I haven't suppressed any of my Vz58s, my understanding is that you should only need something like these if not using a flow through suppressor OR if fine tuning for competition... You can't tune the gas block (w/o DIY setscrew mods -- covered here in archives previously and definitely a semi-permanent alteration and potentially dangerous depending on number of threads engaged since gas block not designed/engineered for such modification) so this piston scheme is an alternative approach.
And where you do need tuning is if wanting to shoot subsonic 7.62x39 suppressed and have it cycle your gun -- in which case adjustability is required to be able to shoot both subs and supers, as it requires you to expand your gas port for subs or suppressed subs and then reduce gas via the piston or otherwise for supers to suppressed supers.
I don't know if they're still available, but nearly a decade ago someone in Canada was selling recoil buffers that were basically rubber discs that installed on the top cover striker spring post between the post's base and the striker spring (search archives here as it was discussed)... If you're worried about excess recoil damaging your gun, that might be the easy way to go, in addition to the common-sense of installing and running new/non-surplus recoil and striker and piston springs so that you know their provenance. And if wanting to fab something custom or plus power, the piston return spring would be where I'd start if not focus my efforts -- it's extremely basic spring and if you up a wire gauge or two and/or add additional loops to existing gauge -- whatever approach doesn't bind and cause malfunctions -- should provide enough add'l braking to counter any ill effects (any non factory modifications are at your own risk however!). Others have also played with surplus pistons (search archives here) and found benefit to using ones with smaller head diameters for muzzle brake or suppressor use in order to reduce recoil impulse/overgassing. You might also see benefit to removing the piston head's small "cup" on a grinder, or potentially reprofiling into a reverse cup depending on how much adjustment you need -- just be aware that you're going be needing to remove the chrome in the process for any surplus pistons... Any reduction in length of piston head moves it closer to vent holes in the gas block and exiting the gas block, but might also induce malfunctions -- handguard top cover helps to keep piston in its proper angle of operation.
Good luck and keep us posted on your efforts and results!
