Hi. My name is Sean King. I'm brand new to the forum and am looking for some help from someone who owns a VZ-58/CZ 858 SBR.
I am in the United States. I learned that Canada is able to import VZ-58s with the shorter bbls (approximately 12 inches or ~304.8mm in length).
I have two VZs....one has a 16" (~406.4mm) bbl; the other I had cut down to 12" by my local gun smith after completing the necessary tax stamp paper work.
The gun was made by D-Technik and had a factory bbl port of 3mm. We tried to get the rifle to run (it's a 7.62x39 version) with the 3mm port size and the 12" bbl but it is short stroking, has weak ejection, and was having stove pipes where the spent case would become lodged between the carrier and receiver.
We opened the bbl port to 3.5mm and then to 4mm (which is HUGE). My gunsmith is at a loss for why it's not running.
I know of a company in Tennessee, USA that has done 3 of these SBR conversions and has been successful in getting them to run with a 3mm or 3.5mm gas port in the bbl. However, that company couldn't do the work on my VZ back in June of 2010 because they had a large order of production AKs that they were building. That is why I went with my local class III builder. I have contacted the builder in Tennessee....but he can't tell me why mine isn't running.
Long story short, I need some measurements if possible from someone with a factory SBR VZ 58.
I am inclined to believe the bbl port is no longer the problem, but that instead the problem may lie in the gas block itself. I noticed the two "gas bleed off" ports on the bottom side of the gas block on the VZ are fairly large.....about 4mm or .157 inches. I am thinking that the gas may be bleeding off too quickly and that the solution may be to weld up the ports and redrill them to keep the system pressurized longer. I also notice that my other 16" (the 12" is at the gun smith so I can't measure it) VZ has a .125" gas block port size that mates to the bbl port. I don't know if my gun smith also enlarged the gas block port when he opened up the bbl port to 4mm....but that may also be the solution we need.
What I need from a Canadian factory CZ 858 SBR owner is measurements of the two gas bleed off ports and the gas block port size.
This can be accomplished by simply removing your piston and using drill bits or gauge pins to stick in the holes and see what fits and what doesn't. I needed a small flash light to see into the gas block to measure that port size but besides that, a set of machinist drill bits, and 5 minutes of your time....that should be all that's needed.
I would sincerely appreciate any help any of you could give with these measurements as I am at a complete loss as to why this gun will not run.
If any of you think I'd be better off asking in a VZ specific forum, please post a link and I will do so. I haven't been able to find any forums dedicated to the VZ 58 specifically so far.
Thanks for your time,
Sean King
Mesa, AZ, USA
I am in the United States. I learned that Canada is able to import VZ-58s with the shorter bbls (approximately 12 inches or ~304.8mm in length).
I have two VZs....one has a 16" (~406.4mm) bbl; the other I had cut down to 12" by my local gun smith after completing the necessary tax stamp paper work.
The gun was made by D-Technik and had a factory bbl port of 3mm. We tried to get the rifle to run (it's a 7.62x39 version) with the 3mm port size and the 12" bbl but it is short stroking, has weak ejection, and was having stove pipes where the spent case would become lodged between the carrier and receiver.
We opened the bbl port to 3.5mm and then to 4mm (which is HUGE). My gunsmith is at a loss for why it's not running.
I know of a company in Tennessee, USA that has done 3 of these SBR conversions and has been successful in getting them to run with a 3mm or 3.5mm gas port in the bbl. However, that company couldn't do the work on my VZ back in June of 2010 because they had a large order of production AKs that they were building. That is why I went with my local class III builder. I have contacted the builder in Tennessee....but he can't tell me why mine isn't running.
Long story short, I need some measurements if possible from someone with a factory SBR VZ 58.
I am inclined to believe the bbl port is no longer the problem, but that instead the problem may lie in the gas block itself. I noticed the two "gas bleed off" ports on the bottom side of the gas block on the VZ are fairly large.....about 4mm or .157 inches. I am thinking that the gas may be bleeding off too quickly and that the solution may be to weld up the ports and redrill them to keep the system pressurized longer. I also notice that my other 16" (the 12" is at the gun smith so I can't measure it) VZ has a .125" gas block port size that mates to the bbl port. I don't know if my gun smith also enlarged the gas block port when he opened up the bbl port to 4mm....but that may also be the solution we need.
What I need from a Canadian factory CZ 858 SBR owner is measurements of the two gas bleed off ports and the gas block port size.
This can be accomplished by simply removing your piston and using drill bits or gauge pins to stick in the holes and see what fits and what doesn't. I needed a small flash light to see into the gas block to measure that port size but besides that, a set of machinist drill bits, and 5 minutes of your time....that should be all that's needed.
I would sincerely appreciate any help any of you could give with these measurements as I am at a complete loss as to why this gun will not run.
If any of you think I'd be better off asking in a VZ specific forum, please post a link and I will do so. I haven't been able to find any forums dedicated to the VZ 58 specifically so far.
Thanks for your time,
Sean King
Mesa, AZ, USA
