Cz 97 sloppy barrel bushing fix

[florida man]

I recently acquired a Cz 97 and sure enough, just I had read, the screw in barrel bushing is sloppily fit.  I know folks are sending them out to get a match 1911 barrel bushing fit.  Somewhat pricey, but also modifies the factory set up permanently.  Another fix would be to remove some material off the front of the slide until the bushing is screwed in tight and properly indexed to the recoil spring plug.  Again, this is a permanent modification to the pistol.  How about a shim between the slide face and the bushing to take out the slop caused by the coarse threads?  McMaster Carr to the rescue.  They sell a bearing shim with an OD of .873 and an ID of .687.  These were available in various thickness up to .010.  The ID is just enough to allow the shim to spin up the bushing threads and the OD is just small enough so that there is no interference with the slide rails.  I had .006 slop in my bushing to slide face.  I ordered a bag of .007 shims and with plenty of elbow grease, I stoned/sanded the shim to a tight wrench fit.  I then used a tapered stone on the Dremel to radius a notch for the recoil spring plug to clear.  Voila.......this bushing is now dead nuts tight and right in the slide.  I have not come up with the perfect technique for re-installing the bushing/shim when removing the barrel for cleaning.  You simply have to tease the shim into position, so that when you tighten the bushing down, everything is indexed perfectly at the 6 o'clock position.  With shipping, a bag of 25 of these shims was less than 20 bucks.

Now will this enhance accuracy?  Cannot tell you that, as I have not put one round through the pistol yet.  This gun has a simply awful(gritty and creepy) single action pull.  Why CZ leaves the hammer hooks so long and undercut so badly is beyond me.  I am not buying this safety factor line of a lot of "positive" engagement is necessary.  This trigger is ridiculous!  I will be converting this gun to SAO.  Another thing I noticed is that the firing pin spring seems very heavy on this pistol.  I believe that this spring is the same one used in most other Cz pistols.  I would like to set the trigger up to break at 3.5 lbs. to be Bullseye legal.  I am hoping a 16 lb. hammer spring and the usual tuning will get it down there, but I am concerned about light strikes due to this heavy firing pin spring.

[Tok36]

    Reduced weight Firing Pin Springs are available from the custom shops. Simply converting to SAO dose not accomplish much other than deleting the DA. A replacement Hammer can significantly improve the SA trigger break due to the shorter Hammer hooks.

Factory CZs tend to benefit significantly from use. 500-1000 rounds fired is advised to fully break in a factory CZ pistol.

[Joe L]

The bushing shim will certainly tighten up the bushing in the slide, and that is a good thing.  But the clearance between the barrel and the bushing will potentially still be a little loose and that is where the barrel may still be a little loose.

Let me offer a little personal experience regarding the 97B trigger parts.  This ain't no 1911.  Modifying the hammer hooks and factory sear doesn't seem to work very well and can be dangerous.  Lots of us have tried it and failed.  You can  buy a CGW sear and hammer for a specified trigger pull for bullseye.  I used a 97B with the CGW "E" bushing and trigger parts in bullseye matches for a few years before changing locations.   Its been a little over 24 hours since I last shot mine (at 100 yards), as I took a 9mm plastic gun to the range this morning.   

And Tok36 is right--the factory parts smooth out a bunch with some use, but the pull will still be way over your 3.5 lb minimum. 

Joe

[florida man]

Joe.......The barrel to bushing fit is very good and the gun now locks up tight.  I have not had any issues with reworking the sear/hammer engagement surfaces on this design of pistol to get a good release.  I was most concerned with possible light strikes with a slightly lighter hammer spring.  I do have a sao trigger and a reduced firing pin spring on the way from  Cz custom.  I don’t want to see primer swipes with the lighter spring in there.  I personally do not care for the Cz b design that has the firing pin slamming into that cross pin.  I prefer the stop plate design of a 1911 or my Shadow 2.  Anyone have any suggestions as to recoil spring weight for a 97 shooting target loads?  We are talking 200 gr swc’s moving at 800 FPS.  I like my brass launched into my catcher, not into the next zip code.

[Joe L]

Good deal, glad you already have some experience.  Some folks that show up here asking about trigger modifications need some stern recommendations!

As far as the recoil spring with light loads, the factory spring seems to work well, once the gun has loosened up a little from new.  I think it is 18 lb, can't remember.  But I only have much experience with 185 gr JHP at about 830 fps.  I don't think you will need to go lighter than a 17.  Mine is borderline too heavy on a cold day with cold ammo. 

Joe

[Fuzzy Sights]

If I recall the 97 has a 13lb factory spring that is identical to the 75b spring.  You can use a Wolff calibration kit to get your brass to go where you want it to.  Believe they make both extra power and reduced power kits.

Best of luck on your project.

JW

[Earl Keese]

Getting a good result by modifying sear to hammer hook engagement isn't the issue. The issue is that the oem parts are surface hardened. To each his own, but as JoeL has said before, the best tool to improve the trigger pull is a credit card.

[SI VIS PACEM PARRABELLUM]

  This gun has a simply awful(gritty and creepy) single action pull.  Why CZ leaves the hammer hooks so long and undercut so badly is beyond me.  I am not buying this safety factor line of a lot of "positive" engagement is necessary.  This trigger is ridiculous!  I will be converting this gun to SAO.  Another thing I noticed is that the firing pin spring seems very heavy on this pistol.  I believe that this spring is the same one used in most other Cz pistols.  I would like to set the trigger up to break at 3.5 lbs. to be Bullseye legal.  I am hoping a 16 lb. hammer spring and the usual tuning will get it down there, but I am concerned about light strikes due to this heavy firing pin spring.

These are service grade pistols not competition ready models so if you want a better trigger you modify that's just the way it is. Go find an unmodified world war era 1911 and try the sorry sad long pull those clunkers had. They were miserable because JB specified .030 hammer hooks which sometimes ran even longer in production. No where near the .017-.019 that some people run on that platform. The good news is the CZ does mod up real well. I use the CGW Pro Pack in all mine and the parts put the guns on plane with many higher priced custom models for a lot less money.

[Dan Wesson]

Following to see how this turns out. I converted my 97b to SAO with CZ SAO trigger and CGWs floating trigger pin. I also removed the firing pin block and lifter/spring, replacing it with the bushing from CGW. My trigger pull weight is down around 4lbs now and quite smooth. I’m sure a new hammer would further reduce the pull, but I’m good with what I’ve got now.
Please keep us updated on your progress.


Sent from my iPhone using Tapatalk

[florida man]

I have heard this claim about the depth of surface hardening on CZ parts for years now.  Is this simply an urban legend or can someone produce real documentation regarding this claim?  I have also heard that some parts are MIM parts.  Looking at the hammer of this Cz 97, I don’t see the mold marks typical of a MIM part.  I have a Tristar T-120 that most definitely has a MIM hammer, as the mold marks are clearly evident.  That pistol has a nice 3.25 lb. pull with the stock sear, firing pin block, and re-cut hammer hooks + a M Carbo spring kit.  That trigger is holding up just fine.  My first Cz was a pre-b 75 that was one of those first ones imported by Action Arms.  I was impressed with the mechanical design, but thought the execution could be improved.  Back in the early 90’s the Tanfo clones were seeing a lot of interest in the action shooting events.  EGW offered a hard sear that sold like crazy, since the word was the oem Tanfoglio sears did not hold up.  At any rate, I installed an EGW sear in my 75, converted it to sao (never had any use for that da feature) and reworked the hammer to get rid of that goofy camming action.  That gun had a completely reliable 2.75 lb. trigger pull with the oem springs.  Never had any issues with hammer follow while shooting or dropping the slide.  I did use some brass shim stock to take the slop out of the sear cage to frame fit.  I don’t recall that pistol ever having a malfunction even with those loosey goosey tolerances.  Not entirely convinced about modified oem parts not holding up, but maybe I have been lucky.......just sayin’

[newageroman]

"...In recent news... a Florida man has impressed the CZ nerds with his previous gunsmithing successes and out of the box thinking...more at 9..."

I like your idea about the shims and I will be trying that. My busing is just a little loose. Another option might be to just hone the backside of the bushing down so it will fit in the next notch.

I like your idea better because it keeps all things back to stock possible.

I can't speak to the surface hardening, but I just buy new CGW hammers/sears, they are noticeable improved over stock. Add SAO to that and dang its sweet!

Very nice commentary - keep it coming please.

[Earl Keese]

"...In recent news... a Florida man has impressed the CZ nerds with his previous gunsmithing successes and out of the box thinking...more at 9..."

Not sure which "CZ nerds" you speak for but most of this is nothing new. Plenty of people have joined this forum over the years and argued that modifying the oem hammer/sear is the way to go. They usually move on after a few posts when nobody lines up to praise them for their amazing discovery.
As for shimming the bushing, yes it will allow it to be tightened to the previous notch. If that makes you feel better, great. It still doesn't account for the tolerance between the bushing and barrel- you get whatcha get.

[tdogg]

I have heard this claim about the depth of surface hardening on CZ parts for years now.  Is this simply an urban legend or can someone produce real documentation regarding this claim?  I have also heard that some parts are MIM parts.  Looking at the hammer of this Cz 97, I don’t see the mold marks typical of a MIM part.  I have a Tristar T-120 that most definitely has a MIM hammer, as the mold marks are clearly evident.  That pistol has a nice 3.25 lb. pull with the stock sear, firing pin block, and re-cut hammer hooks + a M Carbo spring kit.  That trigger is holding up just fine.  My first Cz was a pre-b 75 that was one of those first ones imported by Action Arms.  I was impressed with the mechanical design, but thought the execution could be improved.  Back in the early 90’s the Tanfo clones were seeing a lot of interest in the action shooting events.  EGW offered a hard sear that sold like crazy, since the word was the oem Tanfoglio sears did not hold up.  At any rate, I installed an EGW sear in my 75, converted it to sao (never had any use for that da feature) and reworked the hammer to get rid of that goofy camming action.  That gun had a completely reliable 2.75 lb. trigger pull with the oem springs.  Never had any issues with hammer follow while shooting or dropping the slide.  I did use some brass shim stock to take the slop out of the sear cage to frame fit.  I don’t recall that pistol ever having a malfunction even with those loosey goosey tolerances.  Not entirely convinced about modified oem parts not holding up, but maybe I have been lucky.......just sayin’

Well, a gentleman in our club shot his weak hand during a USPSA practice session at the make ready command when his Tangfolio went full auto upon charging his gun.  I'm not sure he will be able to shoot again competitively.  They had to reconstruct most of his weak hand.  Thankfully nobody else was injured and the gun stopped cycling when he dropped it.

He confessed that he had modified the sear/hammer interface tuning the trigger.  I don't know all the details as to what he did but it did involve modifying the stock parts.  This wasn't his first rodeo and had been shooting USPSA for quite a while when this happened.  I couldn't tell you how many rounds till failure but when it failed it was catastrophic.

I wouldn't advise anyone to modify the hammer/sear interface (or for that matter any safety system) on any gun.  They are case hardened for a reason and it isn't that robust to modifications.  If you're that hard pressed to save a few dollars on parts then I'd advise that this sport probably isn't in the cards.  Other parts that aren't critical to safety/ignition, by all means modify away.  These are tools and should be configured/improved upon as needed.

I did modify the barrel bushing on my 97 but went the opposite direction than you.  I took off just a smidge under the rim of the bushing so it would line up when tight.  I still want to send in my 97 to get the E package someday.  As Earl stated, you can turn it into a bullseye lockup with the custom fitted bushing which you don't get with the stock bushing (even if shimmed/reworked).

Cheers,
Toby

[sevt_chevelle]

I fail to see what you gain by tightening the bushing via shims.
My barrel bushing, let's just say 80s porn star fitment loose on the barrel.

People do the 1911 bushing not because it fixes a sloppy fit at the slide or guide rod plug.
Mine is so tight with 1911 bushing it requires a 1911 bushing wrench to turn than requires with that same wrench and a few taps to move it off the barrel.

You still have a barrel riding inside an oversized bushing.

[SI VIS PACEM PARRABELLUM]

"...In recent news... a Florida man has impressed the CZ nerds with his previous gunsmithing successes and out of the box thinking...more at 9..."

Not sure which "CZ nerds" you speak for but most of this is nothing new. Plenty of people have joined this forum over the years and argued that modifying the oem hammer/sear is the way to go. They usually move on after a few posts when nobody lines up to praise them for their amazing discovery.

HAHA! Yep they move on because they know what they're doing is crap and a crap shoot and it's just a matter of time before it bites them and they'll generally never come back and say yeah you guys were right I screwed my gun up.
I like many tried "modding" a CZ hammer and sear many years ago. I though I've done this with 1911's and I could even cut out a darn good trigger with the fixtures I had purchased for S&W 3rd gen pistols years ago. Well it just doesn't work with the CZ action. The 75B compact I worked on had a really great SA pull but if you rolled into it real slow you could get the hammer to fall to half cock just about every time.
Lesson learned. Properly engineered parts are the only way to go. CGW and CZ Custom flourish for a reason. There's geometry involved in making these parts that a ham handed kitchen table gunsmith just can't duplicate.