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There are quite a few resources out there for us shade tree gunsmiths to work on our CZs, most notably this epic thread (http://www.czfirearms.us/index.php?topic=42537.0) I have linked to many times by David Milam of Cajun Gun Works. While tuning up a brand new SP01, I decided to take a stab at a comprehensive beginner's guide to these great pistols; my hope is that this thread will spark discussion and collaboration so that collective knowledge of this forum can create something really useful for new CZ lovers.

The tools:


I prefer a heavy hammer because it will deliver high energy blows without swinging it too hard (less effort = more control); you can cut down on "idiot marks" and other collateral damage when you swing the hammer with less effort. Because the pins in my Brownells set are too short for some applications I use these basic punches as well:


although it looks like Brownells is now selling longer pins: http://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/punches/gunsmith-replaceable-pin-punch-set-prod545.aspx

The replaceable pins are nice because punches do bend and they do break. You'll see I also use Quick Clamps with rubber boots which do a nice job of clamping the frame/slide down without marring the finish.


By nature polishing metal is about removing metal, but the key is to remove very little amounts of metal at a time; I use a power sander with 1000-2000 grit sandpaper on flat parts and a felt wheel with automotive rubbing compound on those 'hard to reach' spots.

As we become intimately familiar with our pistols, it's easy to become lax on safety, so I began by clearing the pistol.


I tested the trigger pull for a baseline:



Edited by kneelingatlas
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Then I went to work:
Pull the slide slightly back until the take down marks line up at the back of the pistol then push the slide stop out from the right side.
The top end then slides off the front of the frame.
Remove the guide rod, recoil spring and barrel.

I will be installing an extended firing pin, reduced power firing pin return spring and reduced power firing pin block lifter spring, all from Cajun Gun Works.

Edited by kneelingatlas
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I use masking tape to protect the polycoat then clamp the slide to a sturdy bench top or saw horse and pound out the roll pin which retains the firing pin.


You will feel the firing pin pushing on the punch once the roll pin has cleared the channel. I try not to drive the roll pin clear out of the slide so it's easier to put back in. Once out I polish the channel with a rolled up piece of sand paper (1000 grit or finer) and I will spin the new firing pin in a drill or drill press, using sand paper to polish it as well.

I place my sand paper on a folded towel to polish parts which are not flat nor round like the firing pin block.


I also lightly polish the hole where the block goes.

*When polishing metal parts smooth is the goal, if you remove too much metal you can ruin them so I don't suggest using and sand paper coarser than 500 grit*

When the pistol cycles, the leading edge of the slide must fight both the hammer spring and the recoil spring at the same time; to round this edge is the reduce the initial force required at the beginning of the slide stroke, reducing muzzle flip.


Other things can be done here that I didn't do: polish the breech face, chamfer the firing pin hole and soften the bottom edge of the breech face to reduce the slide dragging on the top round in the magazine on its way back. None of the work detailed in this thread is 'necessary' to the function of your CZ pistol, so you can certainly prioritize your time spent tinkering, or do these mods in steps if you prefer.


Reinstall the firing pin, then the firing pin block and lastly the barrel/recoil system.

Edited by kneelingatlas
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Now to the lower half of the pistol:

I will install CZ USA's race hammer, a Shadow mag release, 97B trigger (the same as the old style 85C trigger, but without the over travel screw), a flat hammer spring plug, and the following CGW parts: 11.5# hammer spring, reduced power trigger return spring and type one short reset disconnector.


Step one: remove the grips.


Next depress the hammer spring plug slightly and remove the retaining pin.


Then remove the top retaining pin on the magazine brake and remove the brake.


Removing the safeties: using a jeweler's screwdriver, lift the long leg of the sear spring out of the groove and set it aside on the safety.


Edited by kneelingatlas
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then use the same screwdriver the depress the spring loaded detent on the left hand side and push the left hand safety out to the right.


Pull the sear assembly forward to remove it.


Be mindful of the safety detents in the frame; the right detent simply sits in a groove in the frame while the left one is under spring tension, set them both aside.


Edited by kneelingatlas
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Hammer pin removal: using a jeweler’s screwdriver to push the retaining pin up out of the path of the hammer pin, then push the hammer pin out right to left.



Remove hammer, strut and disco:


Polishing the hammer strut (red line above) can improve the smoothness of the DA stroke as this is where the hammer spring compresses. Punch out the trigger pin starting on the end with less flare:


Edited by kneelingatlas
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The trigger return spring will go flying when you pull the punch out, so cover the top of the frame with your hand as you pull it out.


To change the mag release you must remove the screw holding the trigger bar lifter spring, this screw may or may not be staked and can be very difficult to remove, so use a screwdriver with a tight fit and maintain constant downward pressure while turning.


Edited by kneelingatlas
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The pin connecting the trigger the trigger bar should push right out without hammering.


On the back edges of the trigger bar there are four bearing surfaces:

-the inside two are where the disco breaks the DA shot

-outside left (top in picture above) is where the single action shot breaks at the sear

-outside right (bottom in picture above) is where the firing pin block lifter is activated

These surfaces can be lightly polished, but removing metal will change the 'timing' of the action (more on that in the advanced class...)


This is the surface where the trigger bar rubs on the bottom of the sear cage and should be polished, as well as the top humps where the bar contacts the slide. The sides of the trigger bar rub on the sides of the frame and should be polished.


on the bottom of the trigger bar you can see where it touches the frame and where the U shaped spring rides.

Edited by kneelingatlas
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An important part of the polishing often neglected is polishing the corresponding parts of the frame where the moving parts touch and the insides of pin holes; this can be done by rolling fine sand paper and pulling it through the pin holes.


The hammer pins are sometimes staked and very difficult to remove so a starter punch can be helpful.


Edited by kneelingatlas
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As you can see from the standard hammer on the left, to the stock Shadow hammer to the CZ race hammer, the depth of the hammer hooks have a drastic effect on the single action pull.


When reinstalling the pins I hold them with needle nosed pliers and use a vice to press them in:

When you use a vise to press the pins into the hammer it's important you keep the pin perpendicular to the hammer, otherwise it can bind and break the hammer; as an alternative you can place the hammer flat on a bench or block and drive in the pins with a small gunsmith's hammer like this one: https://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/hammers/3-4-plastic-brass-hammer-sku818600343-12589-30175.aspx?cm_mmc=cse-_-Itwine-_-shopzilla-_-818-600-343&utm_medium=cse&utm_source=connexity&utm_campaign=itwine&utm_content=818-600-343"


It’s important to polish the sides of the hammer where it rubs on the frame.


The easiest way to re install the trigger return spring is to use a slave pin the same width as the trigger which can be made from a finish nail.


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Re attach the trigger bar.


As you drive in the trigger pin, it will push the slave pin out the other side.

The sear cage: reassembly can be tricky, so if you’re not mentally prepared, skip this step :devil:. I'd like to add that you can achieve a dramatic improvement over the stock trigger pull with just a few of these modifications so if you're intimidated by any of this, just skip it and come back to it another time.


Edited by kneelingatlas
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Push the sear pin out taking care to keep the sear spring and firing pin block lifter spring from flying away on you.


The polish the underside of the sear cage where the top disconnector makes contact during the DA stroke.


Roll a piece of sand paper and pull it through the sear pin hole.

also the lifter arm. Be careful with the sear face; polish, don’t sand!

The short leg of the sear spring is very short, so if you want to make a slave pin it has to be tight; I use a punch to maneuver the spring onto the pin.


Edited by kneelingatlas
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IMG_20140124_241009_585_zps0469a7ad.thumb.jpg.75286d6e5bd45aadc6583ac2f1cae70b.jpgIMG_20140124_241219_087_zpsdb7ba558.thumb.jpg.cb5244a20fd8cfc11a3939d36e59d21e.jpgIMG_20140124_241246_639_zpse6694919.thumb.jpg.074b8725cab14301d925f01600864fe7.jpgOnce everything is assembled with the short reset disconnector the trigger may not reset so you will need to remove a little metal from any/all of the following places: the firing pin block lifter arm, the wedge of the disconnector and the trigger bar.


Go SLOW when removing metal, there’s no going back!

Some tips for reassembly:

The hammer pin retainer pin must go back in before the left side safely detent:


Edited by kneelingatlas
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IMG_20140124_241409_316_zps5cc549d9.thumb.jpg.83520652bc679975b429e55b62bc5c48.jpgIMG_20140124_241819_327_zpsf47ded95.thumb.jpg.bdaa97a3829b2e7ce8986ce12f3171d7.jpgInstall the right side safety first, a little grease will keep the detent in place, then install the sear assembly:


Left side safety needs to go under the long leg of the sear spring:


Finally use a jeweler's screw driver to push the left side detent to the rear so you can slide the safety in the last few mm:


Edited by kneelingatlas
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Here are the trigger pull weights I saw attained this work:


And the reset is VERY short :) Theses numbers could be lower with an 8.5# hammer spring and more polishing, but I think this is a pretty good example of a first pass (plus the 8.5# hammer spring will light strike with anything but Federal primers). David recently boasted a four pound, three ounce DA and two pound twelve ounce SA pull with a firing pin block SP01: http://www.czfirearms.us/index.php?topic=61974.msg409657#msg409657 which is as low as I've ever heard of :bow: . I did a Shadow with an 11.5# hammer spring which ended up with a five pound five ounce DA and one pound, fourteen ounce SA, very sweet! :D

Please feel free to add information or debate the techniques I’ve used here; my hope is that this thread can help develop the best ideas for tuning the pistols we love.

Edited by kneelingatlas
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Sick awesome post!

Not many people are familiar with this platform, and I know many more (very experienced) gunsmiths that are just plain intimidated by it and won't work on them.

When I was starting with them it would have been so nice to be able to find a pic heavy detailed thread showing exactly what to do to make em sing.

Thanks, and keep up the good preaching Prof. Atlas, haha!

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If you want a really light trigger you can relieve some of the tension of the trigger return spring by bending it to open it out a little. This will lighten the trigger pull and the trigger reset action. Note that the trigger will not reset properly, or at all, if you are too enthusiastic in bending the spring, but a little bit of adjustment will make a big difference to trigger weight. I do not recommend this adjustment for anything other than competition purposes and I would recommend against doing any adjustment to the trigger return spring for a carry gun.

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Awesome post and photos John .
This will a great resource.

as mentioned some work can be done on the TRS to lighten the DA stroke little more but keep the heavier hammer spring.

when getting down in the low 4# range the reset starts getting a little light, so some maintenance is going to be needed to make the action doesnt get gunked up.

there is going to be a balance between super light actions and keeping reliability of ignition and function.

once you get into this range you are really going to have to reload for the pistol. good bullets, good brass, seating primers correctly etc.

Edited by eerw
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that single action looks short for a SP-01.. nice I couldn't get mine that far back.. damn good job.

I actually took a little off the sear, off the 'foot' of the FPB lifter and the trigger bar where it picks up the lifter to get it that short.

On my SP 01 I machined the ledge on the firing pin that catches the FPB down to .018 thick so that the FPB needs less travel to clear it, then shortened the foot on the lifter to remove the excess travel. Makes the reset pretty sweet.

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