The Original CZ Forum
CZ LONG ARMS => VZ-58 semi auto rifle => Topic started by: Airacuda on April 17, 2014, 02:48:01 PM
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My 1st try at help video. Hope you enjoy.
https://www.youtube.com/watch?v=oArqQoDuWMY
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Very very Interesting! 8) Wondering if that could cause Trigger slap, not that I've had any as yet.
Making this thread a sticky, for the time being.
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This was previously covered here (obiwanbonjovi/bonesteel also details the tab dimensions somewhere in the 12 pages): http://www.canadiangunnutz.com/forum/showthread.php/283939-How-to-get-rid-of-the-infamous-CZ-VZ-gremlin?p=4617775&viewfull=1#post4617775
And the why behind the gremlin is expertly covered over here: http://www.ar15.com/forums/t_4_99/145592_Tabbed_bolt_carriers_and_the_vz58_gremlin.html
The problem with the spring tension mod is that it's not a 100% fix due to 1) the increased trigger pull and 2) that hotter ammo or a weakened recoil spring will result in the bolt carrier moving rearward faster and pushing the sear down where the disconnector re-engages the sear and also the trigger spring itself will weaken over time resulting in the gremlin reappearing.
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P.S. The gremlin problem -- covered in the AR15 article btw -- is due to the autosear that's been removed from the rifle. The auto sear ensured that striker stayed rearward until bolt carrier was in battery/all the way forward. So in semi, both sears are used to grab striker until the bolt carrier was in battery. That disengages the auto sear, which then meant just the trigger pull to disengage the semi sear to releases the striker.
http://youtu.be/oQMh85CnCZE
Here's the actual time stamp for sears: http://youtu.be/oQMh85CnCZE?t=10m
While high level, you have two springs on the Century model and spring adjustment does similar. The spring tension alone cannot always fix the now single semi auto sear being pushed down so far that it re-engages the disconnector, allowing the striker forward. Only the tab is a 100% fix, since it re-releases the disconnector before the striker again crosses the sear.
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Very very Interesting! 8) Wondering if that could cause Trigger slap, not that I've had any as yet.
Making this thread a sticky, for the time being.
I've experienced a similar issue with the rarely discussed Ohio Ordnance VZ2000. I wouldn't consider it trigger slap because when firing, you don't feel it. But when hand cycling, you do feel it......When moving forward, the bolt carrier pushes the disconnector forward (then down), instead of just pushing it down. This causes the striker to drop..........For me, the problem was the radius of the "OOW" marked disconnector.Therefore, I am hesitant to trust CAI and OOW fcg parts....... VZ parts do wear and FCG tolerances are pretty tight...... Like "RSR" said, the only true fix is to tab the bolt carrier....I truly believe the VZ design is superior to the AK design. But when it comes to the FCG tolerances, the VZ can't compete with the AK. In other words, find a reliable FCG- problem solved!.... It's your VZ's only weakness.
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There is also another problem that I encounter....The sear can walk to one side of the pin after a few pulls of the trigger, causing the disconnector to shift off the sear when the trigger is pulled, instead of pulling it down to drop the striker....The issue is caused by side to side movement of the trigger and sear. I've personally seen it twice. Both times, it was the cnc warrior FCG in Czechpoint rifles. It can easily be fixed by adding a shim to the pins, minimizing the side to side movement......Both times, the striker had to be released by pushing the base of the trigger towards one side, in order to remove the dustcover.
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*FWIW -- Not a weakness in the original full auto configuration!
Just the aftermarket setup...
And the wide sears are superior to the narrow ones.
E clips or some folks use 22 lr brass shell casings (there's a youtube) to make a shim for the 2nd issue.
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I've experienced a similar issue with the rarely discussed Ohio Ordnance VZ2000. I wouldn't consider it trigger slap because when firing, you don't feel it. But when hand cycling, you do feel it......When moving forward, the bolt carrier pushes the disconnector forward (then down), instead of just pushing it down. This causes the striker to drop..........For me, the problem was the radius of the "OOW" marked disconnector.Therefore, I am hesitant to trust CAI and OOW fcg parts.......
Glad you posted this on the OOW (Ohio Ordnance Works, Inc.) MDL.VZ2000 VZ58 FCG (Fire Control Group). I had sent OOW an email on this topic a few days ago in an attempt to implement a fix proactively (having several of the OOW VZ.58 variant). No reply as of yet. However, I have NOT seen any post online indicating the gremlin problem crops up on the OOW VZ2000 semi-auto VZ58 variant. I am no expert on these things, but the OOW VZ2000 receiver milled internals and their FCG appear to be different from the CAI and SA (CSA) FCGs. Also, OOW did NOT include the tab on the bolt carrier.
I do actually remember one fellow at OOW saying something about how the VZ2000 was different from other variants because of the trigger problem others experienced, but not being aware of the gremlin issue, it did not mean anything to me at the time.
Has anyone ever experienced, or heard of, the OOW VZ58 developing the gremlin problem? I can not find any post online that confirms the problem exists. Did OOW get it right without the welded tab? What is the "Patent Pending" on the OOW MDL.VZ2000 Receiver for, and who filed it (or, who manufactured the VZ2000 receiver for OOW)?
Here is a 2006 (CZ) US Patent for the VZ.58 Auto to Semi Conversion FGC: Patent Abstract and Image http://pdfpiw.uspto.gov/.piw?Docid=07676974&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsearch-adv.htm%2526r%3D1%2526p%3D1%2526f%3DG%2526l%3D50%2526d%3DPTXT%2526S1%3D%28VZ.58%252BAND%252BReceiver%29%2526OS%3DVZ.58%252BAND%252BReceiver%2526RS%3D%28VZ.58%252BAND%252BReceiver%29&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page (http://pdfpiw.uspto.gov/.piw?Docid=07676974&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsearch-adv.htm%2526r%3D1%2526p%3D1%2526f%3DG%2526l%3D50%2526d%3DPTXT%2526S1%3D%28VZ.58%252BAND%252BReceiver%29%2526OS%3DVZ.58%252BAND%252BReceiver%2526RS%3D%28VZ.58%252BAND%252BReceiver%29&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page)
and full patent...
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=1&p=1&f=G&l=50&d=PTXT&S1=%28VZ.58+AND+Receiver%29&OS=VZ.58+AND+Receiver&RS=%28VZ.58+AND+Receiver%29
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This was previously covered here (obiwanbonjovi/bonesteel also details the tab dimensions somewhere in the 12 pages): http://www.canadiangunnutz.com/forum/showthread.php/283939-How-to-get-rid-of-the-infamous-CZ-VZ-gremlin?p=4617775&viewfull=1#post4617775
Could that be reposted here? I followed the link, but I have to be a member of that forum to read the message. I am especially interested in the tab dimensions and material. Is plain low carbon steel going to do the trick?
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I registered at candiangunnutz and skimmed all 13 pages in that thread. Didn't see obiwanbonjovi post with tab dimensions.
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Had 2 striker resets (gremlin) during range time : 200 some rounds. With tabbed carrier.
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Had 2 striker resets (gremlin) during range time : 200 some rounds. With tabbed carrier.
I think that your post was clear, but I just want to clarify:
Did you pull the trigger, hear a click but no fire, then racking the gun solved the problem? (striker not catching and following the bolt into battery)
Or did you pull the trigger, feel no resistance and hear no click, but playing with the safety selector solved the problem? (safety selector or other part of FCG walking out)
Thanks for any clarification as I just got my carrier tabbed.
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I believe this is also called the hermex effect. VZ58rifle.com has something that looks to be designed to alleviate a second trigger/disconnector slap on the return stroke.
http://www.vz58rifle.com/products/modifikovany-prerusovac-spouste-pro-cz858-a-sa-58/
http://rozpad.cz/forum/download/file.php?id=1703&t=1
http://rozpad.cz/forum/download/file.php?id=1515
However, this looks like it will only work on a double-pull gremlin?
e.g.: It will not work on a 'gremlin' stemming from the striker push-down of the sear such that the sear-foot rotates forward of the disconnector protrusion which can be exacerbated by wear (less likely) or a partial release of the trigger prior to the carrier group's initial contacts with the sear and disconnector.
Tabbing is still the best solution. Though ORF's old compliance package came with a forked extended disconnector intended to interact with the standard carrier nub. However, I hate that the foot on the sear became a rollpin.
http://1919a4.com/showthread.php?16432-VZ-58-build
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foxfyre841 -- thanks for sharing.
Yes, it looks like the extended disconnector accomplishes the same effect as the tab, but it does on the disconnector side rather than the carrier. Interesting nonetheless. Haven't seen the ORF parts before, very cool.
The VZ58rifle.com part, I think due to the pivoting disconnector it functions similarly due to the pivoting upward portion of the disconnector -- increases the range/length of interaction between the carrier and disconnector just like the tab and the ORF disconnector do.
The Hermex effect is what the tab and the ORF part attempt to rectify, as does the VZ58rifle.com part as well.
The other issue mentioned by the VZ58 site is the side to side play that results in you sometimes needing to pull the trigger twice to release the striker when using the original trigger group and semi auto sear only -- e.g., the small sear in your photo not the wider one as utilized by bonesteel and century. Somewhere there's a video out of Canada of them using the base of a 22lr casing as a spacer on the sear pin to accomplish the same (looks like the VZ58rifle disconnector prohibits the sear from that lateral movement).
In full auto, both the left (from shooter perspective: narrower, semi auto) and right (wider, full auto) sears catch the striker in semi auto (due to full auto mechanism, the full auto striker releases automatically when bolt carrier is in batter, allowing the trigger pull to release the semi auto sear once pulled). Full auto, just the full auto catches the striker when the trigger is released. As the semi auto sear was never intended to arrest the striker on its own and is more delicate than the full auto sear, conceptually the semi auto sear is a potential failure point. Whether that is actually a problem, I don't know -- but something to be mindful of. Again, the bonesteel or Century trigger group with the wide sear should make this sear failure null and void.
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Finally an answer I can understand. I bought my vz2008 a couple of months ago an after 600 rnds at the range with no failures, I was trying to figure out how the trigger gremlin could happen. The pics showed a sear that I did not have on my rifle. I can't see a need for tab on a 3rd gen. cia.
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Finally an answer I can understand. I bought my vz2008 a couple of months ago an after 600 rnds at the range with no failures, I was trying to figure out how the trigger gremlin could happen. The pics showed a sear that I did not have on my rifle. I can't see a need for tab on a 3rd gen. cia.
What's your trigger weight? As those trigger springs lighten pressure, it's more likely for the gremlin to appear. As is running hotter ammo like Golden Tiger over lower pressure ammo like Tula... Essentially it's a timing issue and the tab ensures the disconnector is reset (not holding the sear down) allowing the striker to move all the way forward without being caught by the striker...
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The disconnect armature on the strange piece from czexpert is made to move only forward (toward the muzzle). Rather than maintaining contact with the carrier via it's length or spring pressure, it simply prevents an additional reset on the forward stroke of the carrier. If it were long enough to maintain contact with the carrier after contacting the nub, it couldn't pass the nub in the first place.
The best way to alleviate this is to either increase overtravel (can't be done aftermarket because you'd have to add metal to the sear-foot/disconnector-protrusion interaction surfaces) or to change the reset point to precede the sear/striker interaction on the return stroke. This is literally the only way to alleviate reconnection when issues stem from:
1) half releasing the trigger before the striker passes over the sear as moving rearward and then re-pulling the trigger (trigger slap)
2) not enough over-travel built into the sear/disconnector such that the push down of the sear naturally pivots the foot forward of the protrusion. (this can be alleviated by both increasing the sear spring strength and also reducing the vertical width of interaction between the sear and striker THOUGH THIS IS DANGEROUS: the striker may be only barely caught and then release unexpectedly such as when you bump it while aiming at your lover, wife, kid, mom, etc DO NOT MESS WITH THE STRIKER AND SEAR ENGAGEMENT SURFACES).
So: tabbing or get the old Ohio Rapid Fire compliance kit. Or see if whoever holds ORF's patent on the forked disconnector will start making them again.
Here's a neat patent on the tabbing option that shows sear, disconnector, striker, carrier interactions really well!
http://www.google.com/patents/US7676974
Patent is owned by Vladimir Zemanek?
PS: I don't know what steel the carrier is, but it has every indication of being cast steel. Ideally the process is as follows:
Make sure your welder knows this is cast steel and applies pre and post heat treatment. (heat it with propane torach, keep it warm and let it cool somewhat slowly for the first time.) If using low carbon steel (cold rolled LC or a36): after welding shape the tab with file, polish it, and heat the tab to cherry and dunk in casenit. Do this twice and it should be somewhat hard.
Otherwise, grab some 4130, a516/a514 and weld up with a pre&post heats. Normalize (just the tab) once (heat to cherry and air cool). Then heat the tab to cherry, dunk in oil, and place in oven at 450-500 for 2 hours.
Though I'm sure a lot of tabs are just plain-jain 1018 low carbon or pickled a36 hotroll and will last a long time. So the above isn't probably necessary, just would be ideal for longest service. Just make sure the tab isn't harder than disconnector cause the tab can have a bead welded on top to extend if it wears; the disconnector cannot/should-not.
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Okay, I was a little mistaken on how the full auto trigger works:
Under both full auto and semi auto, both the left and right sears are active. The thicker right sear prevents the striker from traveling forward except when bolt carrier is all the way in battery -- it drops from the striker once bolt carrier is in battery and is up whenever the bolt carrier is not completely forward in battery. The thinner left sear is what releases the striker whenever the trigger is pulled. The lever that deactivates the thicker in battery sear is activated by the bolt carrier protrusion, opposite side, that activates the semi auto disconnector.
The only difference in rifle function between full and semi auto is the sears that extend from the full and semi auto disconnectors that extend from the trigger. The semi auto has the upward protrusion. The full auto does not. What happens is that when the bolt carrier first crosses the semi auto disconnector, moving to the rear, is that the narrow right sear is disconnected/released up from the trigger by that movement. To fire again, the trigger needs released/reset and then pulled again. Under full auto, whenever the trigger is pulled that narrow left sear stays down regardless of bolt carrier movement.
Moving the safety forward allows the full auto disconnector to interact with the left sear, while moving safety to the rear allows the semi auto disconnector to interact with the safety...
Obviously different than my original understanding that sears/disconnectors were paired... And obviously when the semi auto conversions remove roughly one half of the fire control group/sear mechanism, it's easy to see why the gremlin occurs. Moreover, it is now apparent to me that the gremlin is also related to not quickly enough releasing the trigger -- didn't fully understand before. So if you hold the trigger back and rearward movement is sufficient to disengage the sear via disconnector but the bolt/striker also pushing sear down so far that it reengages the sear (still having your trigger not fully released seems to be key). Continuing further, jerky trigger pullers would conceptually have less issues than those with good trigger control where pulling all the way to rear through firing cycle and holding to rear until releasing while re-establishing sight picture before pulling again...
The disconnector/sear reset is only about 1/8" to 1/4" of movement. You can see by (with unloaded weapon) and top cover off. Hold trigger to the rear. Push down on disconnector upward protrusion. It'll release the sear. Then push down on the sear (continuing to hold trigger to the rear) to see when it re-engages.
All that the tab does is re-release the semi auto disconnector before the sear has a chance to cross a lowered sear due to momentum, etc.
(http://i.ebayimg.com/00/s/OTcyWDEyOTY=/z/hQkAAOxyHIlTXyrX/$_57.JPG)
(http://i.ebayimg.com/00/s/OTcyWDEyOTY=/z/u2oAAOxyi-ZTXyrZ/$_57.JPG?rt=nc)
Videos:
https://www.youtube.com/watch?v=oQMh85CnCZE
http://www.youtube.com/watch?v=d06hCqcuvsE
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foxfyre841 -- thanks for sharing.
Yes, it looks like the extended disconnector accomplishes the same effect as the tab, but it does on the disconnector side rather than the carrier. Interesting nonetheless. Haven't seen the ORF parts before, very cool.
The VZ58rifle.com part, I think due to the pivoting disconnector it functions similarly due to the pivoting upward portion of the disconnector -- increases the range/length of interaction between the carrier and disconnector just like the tab and the ORF disconnector do.
The Hermex effect is what the tab and the ORF part attempt to rectify, as does the VZ58rifle.com part as well.
The other issue mentioned by the VZ58 site is the side to side play that results in you sometimes needing to pull the trigger twice to release the striker when using the original trigger group and semi auto sear only -- e.g., the small sear in your photo not the wider one as utilized by bonesteel and century. Somewhere there's a video out of Canada of them using the base of a 22lr casing as a spacer on the sear pin to accomplish the same (looks like the VZ58rifle disconnector prohibits the sear from that lateral movement).
In full auto, both the left (from shooter perspective: narrower, semi auto) and right (wider, full auto) sears catch the striker in semi auto (due to full auto mechanism, the full auto striker releases automatically when bolt carrier is in batter, allowing the trigger pull to release the semi auto sear once pulled). Full auto, just the full auto catches the striker when the trigger is released. As the semi auto sear was never intended to arrest the striker on its own and is more delicate than the full auto sear, conceptually the semi auto sear is a potential failure point. Whether that is actually a problem, I don't know -- but something to be mindful of. Again, the bonesteel or Century trigger group with the wide sear should make this sear failure null and void.
I've personally seen the "side to side play" issue twice with the Bonesteel fcg. The parts were deburred too aggressively by the manufacturer. The axis pin holes were bevelled too deep, causing excessive side to side movement. It doesn't take much.
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Just bought 2 vz2008, both have disconecter that is flat on top, put 120 rounds through each, no failers at all. Is it still a good idea to add tab? Or is problem fixed?
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Just bought 2 vz2008, both have disconecter that is flat on top, put 120 rounds through each, no failers at all. Is it still a good idea to add tab? Or is problem fixed?
Without a tab, the problem is never truly fixed.
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Thank you RSR! I Will be sending carriers out to Morgan tomorrow!
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Okay, looking at the trigger function further...
Most of what I wrote previously still applies to some effect (last update described function with trigger pulled, whereas this is a little more full function), but the mechanism is more simple than I previously indicated.
Effectively, the only difference between full auto and semi auto is this:
The safety on full auto holds the left disconnector -- with the hump, same one is our guns -- low enough that the bolt carrier does not contact that protrusion, so the disconnector and the semi auto sear remain engaged and only disengagement is from releasing the trigger forward.
The safety on semi auto allows the left disconnector to raise slightly so that the upward protrusion is pushed down every time the bolt carrier crosses it, thereby releasing the sear up to grab the striker forcing the user to release and repull the trigger for each shot.
So the right "full auto" sear actually functions in both firing types/all the time in concert with the left "semi auto" sear, which also works all the time.
The right sear is connected to a lever/disconnector extending forward (pivoting on trigger group pin) and ending with an upward protrusion that ends just before the bolt hold open (same part but opposite side, the lower rear bolt carrier protrusion) pushes this lever down when bolt carrier in battery, which prevents the striker from moving forward unless the bolt carrier is all the way forward and round in battery. Once the bolt carrier is all the way forward, this sear releases from the striker.
The left sear is connected to the trigger and functions the same all the time. The only difference in function is how the disconnector is and whether the bolt carrier is disconnecting the disconnector from the sear (semi auto) or not (full auto).
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Continuing, the standard gremlin looks to have two primary causes, both of which the tab solves in different ways..
The first is when the bolt carrier travels backwards and hits the disconnector, releasing the sear. The bolt carrier then crosses the sear -- at this point it could potentially push the sear down far enough that the disconnector re-engages the sear. Then hitting max spring tension it moves forward but the bolt carrier recrossing the disconnector (and releasing the sear up) occurs too late for the striker to be grabbed by the sear.
The tab solves this one by rehitting the disconnector earlier so that the sear has time to travel up and grab the striker.
This is also the gremlin that can be temporarily fixed by adjusting the trigger lever spring up for more tension.
This seems to be the most common standard gremlin issue w/ the century guns and is only replicated when firing.
*And probably is rleated to holding the trigger to the rear while the above is occuring. Fairly confident but not certain on this.
The second is related to the first but differently. Essentially, by holding the trigger to the rear the sear and disconnector engagement is so strong that the bolt carrier jumps rather than releasing the disconnector. I belive this to be more of a problem with mil spec trigger groups. I do think Century likely made their sear a little taller to prevent that from happening (need to get a milspec OEM to compare). Mil spec due to the same disconnector pulling the trigger in both semi and full has to be exactly sized so that both function properly. With semi, too tall isn't a problem where the same sear in a full auto gun would have it behave like a semi when at full auto setting.
To the tab, it prevents by making the bolt carrier and disconnector interaction longer timewise and associated angles force so that the "jumping" can't occur.
This can be replicated with cycling your bolt carrier while holding the trigger to the rear.
And again, on full auto guns the right sear is connected to a lever that only drops the sear when the bolt carrier is in battery. So all other times that sear is up to ensure striker is held back...
And the secondary gremlin is the lateral movement of trigger, sear, or safety pins/components.
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A little late on getting these posted, but here are the comparison pics I promised.
Trigger sets. Early VZ2008 top and newer bottom. Note that bottom has a more ramped rear to prevent the bolt carrier from jumping the disconnector when trigger is held to the rear. Also, that nub sticking out on the disconnector grabs the sear.
(https://farm8.staticflickr.com/7539/15552333603_58eeebb5ba_c.jpg)
In this pic (of the Bonesteel/CNC Warrior Sear, not my pic -- it's very similar to the century -- the red circle is what is grabbed by that nub on the disconnector -- when pulling trigger rear, disconnector moves forward which grabs the sear and rotates the sear down). The green circle is what grabs the striker, and the arrow would be roughly up in your receiver.
When pulling the trigger, the initial takeup is what you feel until the disconnector touches the sear part in that red circle and the disconnector engages the sear from the side visible in the pic... Only tension you feel in first stage is from disconnector spring compressing and also causing friction between the disconnector and safety as disconnector pushes up against safety in that safety groove.
The spring tension from the levers and friction between the sear and striker would be the 2nd stage until striker moves forward. You would feel these in harmony. By polishing and greasing sear/striker, you'd minimize that friction and primarily just dealing with spring tension at that point (well tension from stage 1 remains/is cumulative but it's very minimal).
Polishing the face of that sear ledge (the one oriented up and down) in center of green circle and greasing there should improve trigger function while also remaining safe while also polishing forward portion of lower striker that interacts with the sear (you are responsible for your modifications to your firearms. Proceed AT YOUR OWN RISK and ensure proper trigger function PRIOR TO PUTTING AMMO IN THE WEAPON!). You could also polish disconnector/safety parts that interact (upper ledge of disconnector behind the hump and safety groove) and grease those but benefits will be minimal as you can feel with very light initial trigger pull. Greasing sear pin and/or polishing internal sear hole wouldn't hurt either. Same for trigger pin/sear hole (remember to remove the very small roll pin holding in your trigger pin before hammering on it... I made that mistake the first time I disassembled and it resulted in lateral trigger movement after install... Fortunately, that pin is long enough to be reversible, put dented end up.).
After striker moves forward and gun fires, you then have to
1) release the trigger to reset so that the trigger moves forward far enough for
2) that nub on the disconnector to move far enough back to grab/re-engage the sear lip.
To mess with reset distance, you would have to play with disconnector nub locations and/or sear lower lip locations/angles. Conceptually, the further forward the lower sear lip or the further back the disconnector nub, the shorter reset you'll have. Again, only alter fire control group components AT YOUR OWN RISK. *For polishing I'm talking very light, like a little flitz paste or 1000+ grit sandpaper enough to smooth... REITERATING AT YOUR OWN RISK and TEST FUNCTION BEFORE PUTTING AMMO IN THE WEAPON! Every weapon is unique and concepts don't always translate to practical effectiveness, nor have I T&Eed these mods yet.
(https://farm8.staticflickr.com/7527/16146401106_81745f4469.jpg)
Except for when the sear grabs the striker, spring tension holds the striker tightly to the rear of the bolt carrier -- the striker crosses the sear when moving to the rear and can push it down so much that the sear re-engages with the disconnector, begin held down. The downward protrusion of the bolt carrier immediately before the striker is what releases the disconnector from the sear (allowing the sear to spring up under pressure of the lever springs -- it hits that upward hump on the disconnector). When the bolt carrier rearward travel causes sear-disconnector re-engagement, you can get the gremlin as there is not enough time/distance between that downward protrusion of the bolt carrier and the striker for that re-release to be effective, hence the tab which causes the release earlier allowing sufficient time for the sear to rise to catch the striker:
(Not my pic)
(http://i47.photobucket.com/albums/f177/bkpicts/vz58post3-1.jpg)
Safeties -- newer VZ2008 top and earlier bottom. The safeties and or trigger packs can move horizontally, which prevents the disconnector from rising (gap on safety would face down) so that the trigger can pull. The more recent one has this gap widened considerably to prevent horizontal movement from preventing the weapon from firing, earlier just had a small ramp ground to guide it into the notch. Neither add'l grinding is present on OEM.
(https://farm8.staticflickr.com/7544/15984785010_c9cf3105b8_c.jpg)
EDIT: Looked at earlier again today, and I'm confident that those bevels (both side on semi auto slot, one side on full auto) are in fact the factory design -- so original safety was unmodified...
Disconnector -- this is a demo model full auto trigger, so ignore the cutout -- it's specific to the demo, wouldn't be there on OEM weapons and just is there to allow you to see the disconnector/sear interaction. Regardless, the Century and OEM disconnector on the early versions are identical -- no difference in heights or lengths to the rear where it matters or the nub locations...
(https://farm8.staticflickr.com/7553/15549752764_1619472225_c.jpg)
Trigger -- Century uses OEM triggers but grinds them to prevent full auto component installation. Here you can see grinds -- cut off far left ledge in pic, and cut down from left disconnector in pic and then across as well to notch out the top 1/2 of that portion of the trigger. *And you'd need to do substantial modification to your receiver to fit in the full auto components as well. Don't do it.
(https://farm8.staticflickr.com/7567/16171353472_0679aedd54_c.jpg)
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To mess with reset distance, you would have to play with disconnector nub locations and/or sear lower lip locations/angles. Conceptually, the further forward the lower sear lip or the further back the disconnector nub, the shorter reset you'll have. Again, only alter fire control group components AT YOUR OWN RISK. *For polishing I'm talking very light, like a little flitz paste or 1000+ grit sandpaper enough to smooth...
If you attempt mods to improve the reset, can you please please please measure the trigger travel and rest characteristics before and after, while photo documenting your mods in stages. To the best of my knowledge, nobody has attempted (or successfully accomplished) reduced trigger reset distance and feel. This sear/disconnector mod, if successful, would be a major improvement and key at least for me. I would love that crisp break and short reset on a VZ.
My guess is that your utilizing your training cut-away rifle in part to analyze the function of the FCG mechanism. Have you used any marker or chalk of some kind to determine the exact interaction points of the components esp. related to reset?
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I tried this about a year ago and could not get the rifle to function with a shorter reset. I believe you would have to make some custom parts to get it to function. I just got used to the trigger.
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My guess is that your utilizing your training cut-away rifle in part to analyze the function of the FCG mechanism. Have you used any marker or chalk of some kind to determine the exact interaction points of the components esp. related to reset?
Disconnect reset is simple -- it's the relinking of the disconnector nub and sear lip. Disconnector has to travel rearward for that to happen, which means releasing the trigger. That's the extent of the "reset." And why you sometimes have to pull the trigger twice if you don't let it go far enough forward prior to pulling it again... I'm probably going to polish and lube at some point, but highly doubt I'll mess with the reset. It doesn't bother me.
EDIT: That disconnector nub, you'll notice the rear side is angled. That's to allow it to push out and past the sear leg when moving to the rear and it then clicks back tight against the sear to grab it once once past... You can see all of this with your top cover off... Just push down on the disconnector protrusion to mimic the bolt carrier resetting it.
After striker moves forward and gun fires, you then have to
1) release the trigger to reset so that the trigger moves forward far enough for
2) that nub on the disconnector to move far enough back to grab/re-engage the sear lip.
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Very nice analysis, RSR. Thanks for the info and time invested.
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I tried this about a year ago and could not get the rifle to function with a shorter reset. I believe you would have to make some custom parts to get it to function. I just got used to the trigger.
The easiest route is probably to take some material off that back ledge of the sear leg... I'd guess you could take at least 1/3rd the material w/o ruining... You could probably also try messing w/ the disconnector -- adding some more material to the for edge of that nub...
But again, AT YOUR OWN RISK and thoroughly test function PRIOR TO LIVE AMMO. No guarantee that it will work, but it might...
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The difference between hammer trigger systems like on AKs or AR is that the striker system on the VZ58 is that the disconnector release and trigger reset is one in the same on the hammer fired systems whereas on the VZ58 they're separate. On hammer guns you can feel the reset/hammer rise through the trigger which makes it easier (and when you feel the dual reset/hammer rise, you're then good to pull the trigger again). Whereas the VZ58, you feel the disconnect separately and you get a much smaller tactile feedback in feeling the disconnector re-engage w/ the sear...
This animation is the VZ58 (first one is semi auto function and 2nd half is full auto -- you can see the left disconnector with the hump sits lower in full auto so the bolt carrier won't strike and disconnect it, and the right disconnector engages/releases the right sear depending on the bolt carrier's location -- red lines are about where sear and disconnector engage as previously mentioned):
http://youtu.be/d06hCqcuvsE
AR:
http://youtu.be/xh2FjzVVIZY
AK:
http://youtu.be/Ad_4whlPGzU
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I need to clarify a previous misunderstanding regarding sear/disconnector function:
The right sear is connected exclusive to the "in battery" lever. This sear goes down when the bolt carrier is in battery. This sear is controlled, in entirety, by that lever. This ensures that the weapon cannot fire out of battery (and also ensures striker is held back until the bolt carrier and bolt are in battery so that light strikes don't occur like w/ the gremlin).
Since that hole isn't centered (the one in front, where lever connects to the sear), it lowers when lever is pushed down and rises when the lever rises
(http://files.vz58rifle.com/200000236-0376b056a8/striker_catch_right.jpg)
The left sear interacts w/ both the left (semi auto w/ the hump) and right (full auto w/o hump) disconectors. This controls what the striker does when you pull the trigger. Trigger pulled, striker releases... Granted, with semi auto, the bolt carrier crossing semi auto disconnector requires you to re-pull the trigger w/ each shot, thereby releasing and resetting the trigger.
(http://www.ohioordnanceworks.com/media/catalog/product/cache/1/image/500x500/9df78eab33525d08d6e5fb8d27136e95/i/m/img_1096.jpg)
Here is the left disconnector (semi auto) OE from full auto FCG. You can see the ramp towards the rear that allows it to slide by the sear when you release trigger and the front edge that grabs the sear to trip it w/ each trigger pull:
(http://www.ohioordnanceworks.com/media/catalog/product/cache/1/image/500x500/9df78eab33525d08d6e5fb8d27136e95/i/m/img_5518.jpg)
Here is the right disconnector OE from full auto FCG -- I'm not entirely sure about the function of that front ledge but the sear appears to sit between that and the rear portion which is what grabs the sear and serves to pull it forward (note no angle as it is never forward of sear and needing to slide past). Best guess right now, is that it is a safety function to push/hold the sear up when trigger isn't pulled to avoid runaway full auto... And that foward nub would likely work in both semi and full auto modes based upon its location. Also, being located between the two sears, I think this disconnector plus that forward nub helps to keep the sears and disconnectors in proper alignment. (http://www.ohioordnanceworks.com/media/catalog/product/cache/1/image/500x500/9df78eab33525d08d6e5fb8d27136e95/i/m/img_1102.jpg)
Here's what the left OEM sear looks like, the rear of that lowermost protrusion (as pictured) is what the disconnectors pull on to lower and release this sear:
(http://files.vz58rifle.com/200000235-4bc494cbe9/striker_catch_left.jpg)
And with the disconnectors, when the safety is engaged, it pushes them to the floor of the receiver. So that angle cut would lay flat against the bottom of the receiver when the safety is engaged or not in respective fire mode...
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Google translate "ALL CAPS" mine:
Zendl
Modified shutter rod with a circuit for CZ 858 Tactical CZH 2003 Hermex, FSN 01
Modified shutter rod (DISCONNECTOR?) with a circuit (?) designed to help reduce firearm malfunction "Padania dern?ku" (ie. Hermex effect) (GREMLIN?). Defect manifests that after the shot is a new cartridge in the chamber, but the firing mechanism is not tight and not so possible to shoot. On z?palce charge is faintly firing pin (DIMPLE ON PRIMER FIRING PIN?). Adherence to this defect have basically all original automatic weapons Sa vz 58 converted to semi-automatic weapons CZ 858 Tactical, CZH Hermex 2003, the 1st FSN It is due to the mechanisms of self-loading, removing components providing a self-shooting mode, thus changing the function of this mechanism. Using a modified shutter rod interrupter is also possible to achieve lower-trigger using the trigger with adjustable trigger overtravel also shorter trigger travel (SHORTER TRIGGER RELEASE AND PULL?). Before installation, carefully read the installation instructions.
Only malobchodn? (???) sale
2-year warranty from the date of sale
Price without VAT - 1325 - CZK (APPROXIMATELY $50 + SHIPPING)
(http://www.zendl.cz/images/stories/Obrazky/Tahlo_s_prerusovacem_SA58_IGP3114_2.jpg)
Zendl
https://translate.google.com/translate?hl=en&sl=cs&tl=en&u=http%3A%2F%2Fwww.zendl.cz%2Findex.php%2Fproduscts%2Fdoplnkysa58%2F118-vypousteni-zaveru-58
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Does anybody speak enough Czech to order these???
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Does anybody speak enough Czech to order these???
Email them. I have placed orders with them with no issues. Just get your quote in USD.
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done!
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I have a Assault weapons of ohio Receiver, I believe they are the ORF type receivers, Looking for the Trigger Sear and Disconnector, will this disconnected work ?
also which sear should I use and trigger?
Thanks for the help and time! 8)
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I have a Assault weapons of ohio Receiver, I believe they are the ORF type receivers, Looking for the Trigger Sear and Disconnector, will this disconnected work ?
also which sear should I use and trigger?
Thanks for the help and time! 8)
Are you trying to replace or upgrade an existing FCG or fix a non-functioning set? The FCG in the OOW vz2000 includes a sear spacer. You can contact OOW and ask about replacement parts, if that is what you need. I do not know of a compelling reason to install the Zendl disconnector, unless you are not tabbing (adding push down plate) the carrier.
One question: What info do you have that would lead you to believe that the receivers on the OOW vz2000s came from ORF?
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I just read that the (Assault Weapons of Ohio) Receivers were ORF Receivers that they bought up When I believe it was Todd passed away.
I am just trying to get a working FCG into that receiver. Its the type with the original "She 6_ " A 40108 stamping on them.
I bought a US trigger and wide Sear but used the original disconnector and it binds instead of pushing down easily.
I know they use to sell a U.S. 922r compliance kit with these a while back, and not sure what I need to make this run correctly.
Thanks for the help and time!
Not sure if I can ad picture with only 2 posts but I'll drop it here to see:
/Users/gumijagr/Desktop/ORF_Compliance_Parts.jpg
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I just read that the (Assault Weapons of Ohio) Receivers were ORF Receivers that they bought up When I believe it was Todd passed away.
I am just trying to get a working FCG into that receiver. Its the type with the original "She 6_ " A 40108 stamping on them.
I bought a US trigger and wide Sear but used the original disconnector and it binds instead of pushing down easily.
I know they use to sell a U.S. 922r compliance kit with these a while back, and not sure what I need to make this run correctly.
Thanks for the help and time!
Not sure if I can ad picture with only 2 posts but I'll drop it here to see:
/Users/gumijagr/Desktop/ORF_Compliance_Parts.jpg
I totally misread your previous post. My mistake. I am unfamiliar with "assault weapons of Ohio" firearms. Perhaps you can post a pic of the receiver internals or the FCG.
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AWO receivers are the same (or very similar) to the ones on the first gen VZ2008s. Effectively, they are close copies of the dtechnic receivers... I am not sure how they treat the internals however. As I recall, you should be able to install all of the fcg OE parts kits parts, except for the the right disconnectors in battery lever.
This thread might be useful: http://www.theakforum.net/forums/14-general-discussion/38545-vz58-receivers-now-prebuy-group-buy-250-closed-55.html
The 922r kit that was originally sold:
(http://www.hunt101.com/data/500/ORF_Compliance_Parts.jpg)
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Thanks , CP
That was the picture I tried to upload, just cannot find those parts anywhere, I will keep searching:(http://www.czfirearms.us/Users/gumijagr/Desktop/ORF_Compliance_Parts.jpg). still can't figure the picture upload, I will look into that,
RSR : thanks for the thread I did read that earlier before my post, that was where I found that picture as well, just can't locate the parts, I just need the : Disconnector , Sear, Sear Pin, Safety lock, and Trigger.
I'll go back original I guess if I can't find them.
I do have 1- 23049 trigger and 1- Sear from CNC Warrior but think I need the pictured parts instead
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Numrich should have the parts, and if not them then perhaps czechpoint or apex...
Typically on these guns, 1-3 of the parts come through the FCG... I would think if you're building from scratch w/ a kit (what I read into it), then the OE fcg parts should be there... ORF/AWO aren't exactly known for precision w/ their receivers, so my point was to install OE first to check function, before you start trying to troubleshoot.
There are not exact US parts made to OE. Bonesteel is probably easiest to source. You might be able to talk czechpoint into selling them, but I wouldn't count on it as they only seem ot have any interest in supporting only those folks/weapons that were purchased from them/CSA/Dtechnic.
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Yea I know what you mean on them holding there own parts , I am putting on the original parts first ,
as you said to check function and go from there,
trigger just disconnects when putting round into battery,
and bolt carrier rides back over disconnector
I think i need to file small amount off of sear so it can reset itself,
then should be ok
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Actually just squared the trigger opening corners, that were slightly rounded, and trigger is good to go now disconnect resets fine, just need safety lock to hold sear over and all will be fine again. Once I dropped all parts in I could see that pushing or trying to let trigger go after pull and have it snap forward it was just off a few .000 , light file in corners to square let it go by itself now , should be ready to test fire now, then I can park it and paint or may just leave it parkerized state.
Great help on here !
Thanks again for quick responses.
Hope this helps any one that has similar problem with these receivers, I know I saw another thread that said they opened up the trigger opening more, so I know it was
another known issue, and Normally with your stock parts you don't have to file or cut etc. the original parts (if holes are at spec dimensions).
Receiver not being original would or should point you to fitment in that area first.
Always check over and over, measure and read as much about your build before cutting welding or grinding, and ask others.
You can always find help and others that may have had same problems 8)
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New?? http://www.sa58.cz/products/uprava-spouste-sa-58-vymenou/
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New?? http://www.sa58.cz/products/uprava-spouste-sa-58-vymenou/ (http://www.sa58.cz/products/uprava-spouste-sa-58-vymenou/)
Looks like the Zendl DC on a trigger pack. Can't tell if trigger is modified or new/modified. I have operated the DC for sometime now with zero issues to date.
http://www.czfirearms.us/index.php?topic=63408.msg493030#msg493030
http://www.czfirearms.us/index.php?topic=73347.0
http://www.czfirearms.us/index.php?topic=70583.msg504607#msg504607
There is no trigger or DC/trigger combo shown on the Zendl website.
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The set screw to prevent trigger overtravel on that trigger pack is certainly new... Otherwise, it looks like a new old stock surplus trigger w/ the Zendl disconnector on it.
(http://files.sa58.cz/200015610-1aff01bf91-public/P1080997_1.jpg)
(http://files.sa58.cz/200015607-15234161db/P1080999_1.jpg)
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The set screw to prevent trigger overtravel on that trigger pack is certainly new... Otherwise, it looks like a new old stock surplus trigger w/ the Zendl disconnector on it.
Yeah, I'm keen on that set screw.
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Recommended to FM that he integrate something to that effect to his mods...
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I have a Assault weapons of ohio Receiver, I believe they are the ORF type receivers, Looking for the Trigger Sear and Disconnector, will this disconnected work ?
also which sear should I use and trigger?
Thanks for the help and time! 8)
The Czechpoint parts work. I used them in one of my builds.
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Is there any way for me to know if a VZ2008 has the Gremlin issue before shooting it? (Read before buying it...)
Thanks!
S11