Fitting CZ 75 Barrels

[Tok36]

Sounds like you had the right idea pdxrealtor. I was thinking somewhere along these lines but i did not take into consideration the hardness of the V block being an asset nor the use of a feeler gauge. I was also unaware just how little material could be removed each pass and that both lugs are fit at the same time and remain parallel. I had assumed that you fit each barrel lug individually.

This is one of the many times in CZ gunsmithing that i wish i had a machinist background.

[1SOW]

Either make or buy a pillar file (cuts on one side, does not cut on the opposite side)

schmecky,  how do you "make" a pillar file?? Single cut fine file?

If you have a CZ with a "slightly loose fit",  is it ok to take a 001" or so more off the breach face to tighten up the fit into the lugs?

[schmeky]

1SOW,

I like to use a knife edge fine cut file.  I simply grind off one side of the file using a bench grinder. 

About the other question, I would say no, since the clearance of the barrels breech face to the slides breech face is more critical than the upper lug fit. 

[1SOW]

Thanks David.  Just curious.

Did seem it would effect Firing Pin strike and more.

[SpartacusKhan]

The best method for home fitting is with a small V-block.  Either make or buy a pillar file (cuts on one side, does not cut on the opposite side) and you can remove as little as .0005" at time, very precisely, for a truly perfect, parallel fit.

We fit them so that when you press the barrel into the upper lugs the barrel will not fall out of the lugs, but when you just barely touch the top of the barrel hood, it will drop.  This is ideal.

Sorry for reviving an old thread, don't even know if anyone will even read this, but here goes: I just got a new match-grade threaded barrel for my SP-01 Shadow, and it dropped right in, as perfect as I can tell. Got good lock-up, similar fit to my stock barrel, but tighter side-to-side. There are no lugs on the breach face like on the stock barrel, though, just a small cut-out for the extractor. As described above, when I press the barrel into the upper slide lugs, it fits (easily) with no play, but the barrel will drop right back down, no pressure needed. Of course it stays up with the recoil spring installed, but otherwise, not by itself. I can't see any space between the breach faces from underneath, magnified, nor around the port - it all looks like it's touching just barely. I put about 5 rounds through it, firing pin indentations are all dead center on the primers, but haven't had a chance to check for accuracy yet. Could I have just gotten that lucky with the fit? Are my dimensions too loose? Am I looking a gift horse in the mouth? I just can't believe (so far) that I had to do absolutely nothing whatsoever. Pic of the ejection port and looking under the feed ramp with a flashlight through the barrel:

[Tok36]

While i have heard of other occasions where CZ barrels just dropped in, i am unclear on the likelihood of this happening with a CZC replacement barrel. Hopefully another forum member will chime in with more info.

[SpartacusKhan]

Thanks Tok. I guess I'm just thinking it's too good to be true. I expected to have to fit it, and I bought tools. TOOLS, MAN!
More pics, barrels old and new:

[M1A4ME]

I've only fit the one barrel, in my Pre B CZ 85 and I had to remove metal from the left side (the little metal pad that sticks out.)  Same spot the original barrel had material removed, too.

I did buy my brother a new barrel for his SA 1911 a few years back.  It was an aftermarket barrel (don't remember the brand) and it dropped right in but was a little bit tighter fit than the original (original had a swelled spot you couldn't see in the chamber but it would spring brass, about 3 from every 8 rounds that went through it.)

If it drops into place in the slide and the slide can go all the way forward when mounted to the frame it sounds like you've got it.

I read about broken CZ slide stops every so often here on the forum and I wonder if its a barrel that isn't quite right down there in the "kidney bean" hole and the slide slamming forward causes the inside of the kidney bean surface to really whack the snot out of the slide stop pin harder than is good for it.

I bought a new slide stop for mine and only installed the left side piece (the newer right side slide stops won't fit the Pre B frame) because I wanted the new barrel and new slide stop pin to "wear in together".  Not a gunsmith but I know it's not a good idea to install new pieces to old pieces in a car engine/transmission.  I've seen some hellacious quick wear/tear in valve trains when people (me one time) only replace some of the pieces during a rebuild.

[Tok36]

Good pics, i was unaware that the two barrels have different lug configurations. The CZC barrel dose not have the upper protruding lug like the factory CZ barrel. I am unclear on the purpose of this upper lug, i assume its absence from the CZC barrel means that it is not crucial for the function of the barrel.

I am curious how accurate the new barrel is. Accuracy would be the best proof of its fitment regardless if it was intended to drop in or not.

[Boris_LA]

Good pics, i was unaware that the two barrels have different lug configurations. The CZC barrel dose not have the upper protruding lug like the factory CZ barrel. I am unclear on the purpose of this upper lug, i assume its absence from the CZC barrel means that it is not crucial for the function of the barrel.

I am curious how accurate the new barrel is. Accuracy would be the best proof of its fitment regardless if it was intended to drop in or not.

I would think its there for function of LCI (Loaded Chamber Indicator) for the models that have it. The same barrel goes to all variants of the pistols of this size.

[SpartacusKhan]

The LCI idea seems likely to me, I hadn't thought of that, and the breech face could easily be cut/filed/machined to leave space for one, like on the stock barrel. If by size you mean the SP-01 variants, yes, barrels are thicker than other 75 barrels, being milled from .40 blanks @ .550"
Tok - the top-most breech face lug on my original barrel measures a full 2mm longer than the rest of the breech face (except for the extractor cut-out), and there is a corresponding cut-out in the slide's breech face. Now that I think about it, maybe it's to lock-up against rotation? In any case, the new barrel has much less play (side-to-side or rotation-wise) when just dropped in the upside-down slide than the original barrel. You can see in these pics how much thicker the chamber support area is along with a beefier lower lug, so that certainly contributes to the tighter fit. Hopefully I can try to test accuracy tomorrow. Anyway, I find the comparison between the two barrels very interesting, and hope it was money well spent for more than just having threads (which will pay off in less than a year I hope for suppressor approval) in that the match quality and added length make for better accuracy. I still need to get a bushing, though. Anyway, enjoy the pics and anyone feel free to weigh in please.

[Boris_LA]

If by size you mean the SP-01 variants, yes, barrels are thicker than other 75 barrels, being milled from .40 blanks @ .550"

I meant that different CZ 75 9mm variants with standard barrels (not SP-01) use the same universal barrel regardless if they have LCI or not. Makes cheaper and practical to manufacture.

[pdxrealtor]

I agree with the other poster- if it drops in and operates it sounds like it's good to go.

The instructions earlier in this thread explain how to file it down, and when it's done. Sounds like yous is done without filing, no?

[SpartacusKhan]

Seems that way, just thought too good to be true. It actually fits a bit tighter than the original barrel except at the breech faces, where the fit seems the same, though there's no upper protruding lug to fill the space in the pics on the breech face of the slide (above the firing pin hole). With unchanged iron sights, I put 5 rounds today through the same 1/2" ragged hole @ 10-11 yds to test for accuracy, so it's dead on (POA=POI) at that short distance, anyway (using regular Win white box 115gr fmj). I don't have a longer space with a berm on my property, so more testing will have to wait. I have some 147gr and will pick up some 124gr to run through it too. This one likes lighter Hornadys a lot, at least before the barrel change, but will eat absolutely anything, same as the P-01 I have. Anyway, this small test at least put my mind to rest, function seems fantastic, so I guess I should not look for problems.

[srREXed]

Did you by chance contact CZC to confirm you've gotten lucky? Normally this wouldn't be a second thought to me, but as a competent part time armorer, I'd say luck is never the case... Match grade components that do not require fitting for proper operation seem wonky to me. I would take a caliper and check clearances and sizes from all contact points of your original barrel and compare them to your custom barrel. If it fits it ships, but it can cause something down the road to boggle. Broken slide stops are a plethor, and they get broken because of the kidney cut on that lower lug. Make sure the travel distances all measure up. I'd hate to see something beautiful end up causing an ugly problem... Only my .02.


FYI this is an excellent thread fellas. Make sure you're paying attention here.