trouble with CZ single set trigger

Discussion in 'Technical Questions & Information' started by scottmi, Jan 5, 2008.

  1. scottmi

    scottmi New Member

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    just received my new CZ 550 FS in 6.5x55 swedish (yeah, it is BEE U TI FUL!) and while going through the motions with it and dry firing, i'm finding that the single set trigger ( SST ) fails to fire at least half the time. pull back and it just drops back into regular location for normal pull WITHOUT triggering. as you can guess, this is a bit disappointing, as well as maybe disturbing. what's going on in there that it only works _sometimes_? Anyone with a CZ SST trigger found this same thing? Ideas? Solutions? thanks.

    pic can be found here: http://www.cz-usa.com/product_detail.php?id=17
  2. LDBennett

    LDBennett Well-Known Member

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    scottmi:

    A set trigger has two sears: The one normally found in all guns and the set one. The way it works is when the gun is cocked and you set the set trigger, it only takes a very light touch on the trigger to let the set sear loose. The set sear is placed a short distance from the normal sear and gains velocity and momentum from its travel to the normal sear. It hits the normal sear and knocks it off, firing the gun. Both sears must have meaningful sear engagements. The normal sear has the standard safe engagement but the set sear has absolutely minimal engagement. Once it is set almost anything will knock it loose and the gun will fire. The set trigger should not be set until the gun is pointed down range and the rifle is in a firing position. Just brushing it with the finger is normally enough to set it off. It can be extremely sensitive. I adjust mine to a little higher level than the rifles are delivered with.

    Your problem, I'd bet, is that the set trigger sear engagement is set to be too little. The adjustment is commonly called the set trigger pull adjustment. Your CZ manual that came with the gun should help you adjust that set trigger to a place where it will have a safe amount of engagement. Right now it is set to too low of a pull level. Get out the manual and attempt to adjust the SET TRIGGER pull level to a more reasonable point where it will actual engage safely.

    If that does not do it then the gun has to go back to CZ. But before you send it back you might want to inspect the trigger assembly for anything that might cause the set trigger sear to not engage correctly (like a piece of dirt or ????)

    LDBennett
  3. Bindernut

    Bindernut Well-Known Member

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    LD is right on the money. I too will guess that the "set" engagement is adjusted too light.

    My 550 (also a Swede...great cartridge!) was the same way when I picked it up...BUT the previous owner had been inside the rifle and had tweaked every adjustment on the trigger EXCEPT the set engagement. (That was the only screw that wasn't burred up and only jam nut that was still tight.) Probably why I got a like new rifle for the price of a beater too.

    An hour or so after I got it on the bench I had a sweet primary trigger and I also cranked up the set trigger a bit too. I don't use the set very much...I don't like the super long overtravel after it breaks. The primary trigger is very clean on mine. I've got it set for 4.5lb.
  4. LDBennett

    LDBennett Well-Known Member

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    I have also adjusted the normal trigger for a reasonable level for both sear engagement and pull level. As I shoot 99.9% at paper targets off the bench, I do use the 550's set trigger but have it set a little heavier than probably most have theirs set for.

    I have two 550's and a 527 with set triggers. The 550's set trigger is a little more precision in feel than the 527's set trigger. I use the set triggers on the 550's but find the 527 shoots just as well with the properly setup normal trigger as with the set trigger. The normal triggers on the 550 and 527 rifles are superior to most other manufacturers trigger regardless that the CZ's have the option of the set feature. I probably am "preaching to the choir" here but CZ rifles are by far the best value in comparison to anything made in the USA. I own Remingtons, Winchesters and Rugers only because I can. If I were limited to fewer rifles they all would be CZ's!

    LDBennett
  5. scottmi

    scottmi New Member

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    thanks - i am hoping it is simply a matter of adjustment. still, it concerns me that the sear does NOT release (to fire) half the time when set..it just pulls back to pre-set position, as if i hadn't pushed it forward to set.. same as taking it off set when the safety is on. as it is now, i can push it forward to set position, then smack sides, bounce heel, shake etc the rifle and no fire. and half the time the set will trigger when pulled, half the time, just as if taking if off. it seems that if i smack the sides of the receiver a time or two, it then works more often, as if bumping it helps the set sear to engage properly. will call CZ about it during the week and see if a tech there can't talk me thru checking adjustment. it's just too wierd i think that it is not taking the "set" half the time. much easier to understand if the set was too sensitive.
  6. LDBennett

    LDBennett Well-Known Member

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    scottmi:

    The adjustment procedure is in my manual and I suspect yours too. Just adjust it but pull off the stock and see if anything is amiss first. It could be something in the trigger assembly that's not suppose to be there, like a small piece of dirt or a burr or?????

    LDBennett
  7. scottmi

    scottmi New Member

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    have the action out and on examination, is pretty easy to see and simple to understand sear/hammer setup. i'm guessing a good blast of gunscrubber, then good oil grease and some finer adjustment will resolve this. not willing to take it apart to polish the sear face (not yet anyway) but that could sure make it nice too i bet. pics later...!
  8. scottmi

    scottmi New Member

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    now it is a GREAT trigger!

    Not too long to sort this out..!
    my guess for the problem was that I needed to ease/lighten the standard trigger pull so the set trigger fall would consistently cause the hammer/sear to break. see pics below to help with discussion.. the way the set trigger works is like a domino effect.. when it is set, the Set Trigger Lever (54) is engaged, and is spring loaded... the trigger has a nice, slight sear surface where it engages the Set Trigger Lever so is easy to trip.. and when you do pull it lightly, the now spring loaded trigger smacks forward against the Trigger Lever (50) with enough force to clear the Sear (36) and voila. My trouble was the Trigger Pull adjustment was adjusted up just a touch too much (too heavy) so the set trigger's spring loaded force didn't give the Trigger Lever quite enough of a smack to overcome the pull weight.. (you're all with me, right?) It is crystal clear when you look at it on the bench. ;)

    So to resolve.. standard trigger adjustment..
    first, terminology and naming: I'm using the names as identified in the manual's List of Parts, with the diagram number. The adjustment screws also are depicted in another image with letters A, B, C, D.. i'll list these too when referring to that part or adjustment. ok...

    [​IMG] [​IMG]

    I like lighter so eased A, theTrigger Pull Adjusting Screw (60), all the way out then back in until just set against the Trigger Pull Spring (59) at it's lightest. before i could adjust this however, needed to loosen/remove C, the Overtravel adjusting pin so i could get at the nut here with a wrench. i had to use a crescent, as don't have a 5mm open/box wrench (but i SHOULD get one). The locking nut on this, A, used a 7mm wrench (which i did have).

    Then adjusted B, Trigger Travel Before Adjusting Pin (58) in to a comfortable minimum. Need to watch this that you don't come in too much, or you can't even engage the sear as you can prevent the Trigger Lever from travelling back enough to rest under the sear. A few cock and pulls and you'll find something nice. Needed a 3mm precision screwdriver for this.

    Then adjusted C, Trigger Overtravel Adjusting Screw (62). When i can, i always like to minimize overtravel. easy to turn this in until find the minimum that worked to suit me. now have about 1/16 of an inch total travel at bottom of trigger.

    Finally, adjusted D, the Set Trigger Adjusting Screw (53). Screwed this in about 1/2 turn and removed the little bit of creep that was present. Not even close to a hair trigger (I do NOT like those) but oh so much lighter than the standard. I don't have scales, but i'm guessing on the order of an eighth of the weight.

    Annointed here and with oil and there with a light grease and now, a comfortable, crisp trigger, and really nice set trigger that works every time. Both passed Rigorous bump and jam tests. Hooray!

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    *pics are before cleaned/adjusted.
  9. DWARREN123

    DWARREN123 New Member

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    Sounds like it needs adjusted. It can also be set up to be used like a regular trigger with little or no creep, crisp break and little or no overtravel. When adjusting do very small adjustments and check often. One adjustment can also affect another, I believe there are 4 screws to be adjusted.
  10. LDBennett

    LDBennett Well-Known Member

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    scottmi:

    Great job on the trigger operation notes! When you seemed to hesitate on my suggestion that you adjust the trigger and seemed to want to send the gun back to CZ, I thought you might feel inadequate to work on the trigger. Obviously that was not the case once you got into it.

    The CZ set trigger is a good design for a commercial non-custom rifle. Once you understand how it works (which you obviously now do) adjustments are as easy as "falling off a log". But let me add a few safety warnings.

    1.) Make sure you have some primary sear engagement. It is easy to maladjust it so that the two parts are sitting edge to edge and not overlap engaged.

    2.) To adjust the overtravel stop, adjust it until the trigger and sear will JUST not reset. Then turn the adjuster towards more overtravel by about a 1/4 turn. That assures the trigger will always reset. That little excessive overtravel will not be noticed in operation and it assures the trigger will reset in all temperatures.

    3.) Get a pull gage to assure you have not adjusted the trigger outside of the CZ specs. I highly recommend the Lyman Digital Gage

    4.) CZ's manual suggests safety tests for adequate sear engagements. Do run them as per the manual to assure the gun is really safe.

    I do all my own gunsmithing work mostly because I hate to send any gun back to the manufacturer since it often leads to months of delays. My experiences with Warrantee Stations is the same as my limited experiences with independent gunsmiths...I feel I know more about it than some of them. So I do all my own work, where I can.

    Good job!

    LDBennett
  11. Bindernut

    Bindernut Well-Known Member

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    Yup, very good job on the documentation scottmi!
    Glad you got things working without having to send it off anywhere. It really is a nice trigger setup isn't it? The only thing I'd like to see different would be a separate set fly(?) piece so that the "set" function wouldn't have that long overtravel when it breaks. Not a big deal to me since I'm not planning on using the set much on a large game rifle but I am seriously considering a 527 for varmints/yotes and I think I'd use it much more with that type of rifle.

    Didn't your set engagment screw have a locknut on it? Hw bout your CZs LD? MIne does.

    One more question on the lubrication...
    Do you live in a cold climate? I have always used powdered graphite on my triggers since even light oil has a habit of gelling up when things get down to the 10 degree mark.
    Last edited: Jan 7, 2008
  12. scottmi

    scottmi New Member

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    no lock nut on D, and didn't see/notice one on B - only locknuts on A and C.

    the 6.5x55 SE cartridge is such a great, versatile, and accurate cartridge that i hope this CZ 550 FS will hold up it's end of things (as for me, well, that's my problem, right!?) It will be deer rifle mostly...but can easily scale up a bit and down a lot. i expect to use set trigger for if ever i go varminting, and/or whenever the oppty my present itself (i.e. deer stand).

    Not ever too cold where i live (Pacific Northwest) but if it does get so cold, hey, this is a Gentleman's Rifle, and the Gentleman stays home if it's too damn cold! ;-) But seriously, have never run into that problem..it is rarely below the 'teens in these parts, even at elevation, and the next thing to never for any extended period.
    Last edited: Jan 7, 2008
  13. Bindernut

    Bindernut Well-Known Member

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    Wonder why mine has a nut on the set adjustment.
    The nut looks the same color as the one on the overtravel screw (kinda dull silver plating)...not blued like the pull weight adjust locknut or the shiny zinc that you see on most bargain store hardware. I think it's metric thread too so I doubt the original owner put it on, but with as boogered up as my adjustments were I spose anything is possible.

    I fell in love with the 6.5x55 after I got my first M96 many years ago. Easy on the shoulder and accurate as heck. Doesn't do too bad on coyotes either with a 140gr SP at mild Mauser-load velocities. I've went through several surplus Swedes and wound up with my current M38, but I always wanted the cartridge in a modern rifle too (I missed out on the 700 Classics in 6.5 but a friend has one). My CZ is just as sweet as his little Classic!

    Up here the best hunting is always when it's down near the zero mark! :D
    Last edited: Jan 7, 2008
  14. scottmi

    scottmi New Member

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    looks to me that the theory is you can change the set trigger adjustment without taking apart the rifle..the screw is just right there in front of the trigger and not hard to access. so at least in these later models (mine is 2007 vintage) perhaps they removed this jam nut as that would kinda get in the way..the parts diagram in my manual does not show a jam nut for B or D.

    maybe the previous owner (or his gunsmith) added that special-like, just because. you know, it's the kind of thing previous owners do. !!
    Last edited: Jan 8, 2008
  15. seanj

    seanj New Member

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    I have been looking at the CZ 550 Lux for a while now. Beautiful gun and has the iron sights like hunting rifles should at least start with. The only reason I've taken so long to buy one is the trigger. The dealer let me dry fire the gun so i could see what the set trigger was like. It went off nice and light the first time, but the second time the set trigger(pushed forward) moved but didn't set off the firing pin. I tried 5 more times and it didn't function 2 more times. The dealer thought i wasn't pulling staight back and I did notice it work better pulling straight back but it failed once more so I left.
    I have since tried 5 other CZ 550 Lux's in differerent calibers and have found the same problem with them all so I'm begining to think it's me or the way the guns are set up coming from the factories. Has anyone else encounter anything similar with CZ 550's? Any remidies or help would be great. Thanks.
    Last edited: Nov 15, 2011
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