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Discussion Starter · #42 · (Edited)
I got home with just enough light left for some informal testing. I was really surprised at how well the old barrel grouped to be in such bad shape. It got too dark to take a picture but it looks like less than 2" at 20 yards offhand. I need to oil the trigger bar(reassembled dry) and the action so the trigger will reset but it is going to be a nice shooter and i am extremely happy with how the brown looks. The new sights are just awesome! I ordered a set of LOK Bogies and an extended slide lock to install. The manual safety lever still has some pits i need to work on but other than fitting the new barrel, which i am now sure will make this a match grade gun, i am just about ready to call this one done.

 

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Discussion Starter · #43 ·
The new barrel is arriving here on Saturday. It will be interesting to see how it compares to the old one. Weather permitting i will shoot a benched group with the old barrel and another with the fitted barrel. It looks as if the old barrel is going to be hard to beat.
 

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Discussion Starter · #46 · (Edited)
The new barrel showed up today. Taking a few measurements tells me how really worn out the old barrel has become. Even with the 10X bushing in place the old barrel literally falls out of the slide. The new barrel was a bear to get in the slide with the match bushing installed.




So after figuring out how to get the barrel popped into the slide the fitting process has started. There are 2 fitting pads on the rear of the chamber that you need to reduce to make the new barrel lock in place. In the picture below the left pad and the small triangle at the top right of the chamber will be the only 2 areas that material will be removed from.




First you will want to coat the fitting pads with either Dyechem Blue or a Sharpie works pretty good too. Once the pads are colored install the barrel and put some rearward pressure on the barrel lug and move the barrel up and down in the slide, where the color is removed from the fitting pads is where you want to start stoning. I use a ceramic medium stone until the color is almost gone and then i will switch to a fine stone for the final fit.





The first trial fit looked like this. I will keep slowly removing metal with the medium stone until you see the black color steadily leaving the pads and moving down. Each time you do a trial fit the color removal should evenly move down the pad. Take your time and stone the pads as flat and perpendicular as possible. Check your work often and don't hurry this process.



Notice no color is being removed from the small triangle yet as i progress.



Almost there. The color has moved down the pad and away from the triangle so now the barrel is squared up in the breach. It is time to start using a fine stone and very carefully removing small increments until the barrel will snap into the locking lugs and stay there with only a slight push to dislodge it. I will also remove the firing pin and insert an empty deprimed 9mm case in the chamber, then view the primer hole location from the rear of the slide to make sure the primer hole is centered with the firing pin. If it is not and the locking lugs on the barrel are fully engaged you will need to remove metal from the lugs until the barrel is centered with the firing pin.



The barrel is now fitted to the slide. The barrel will lock into the slide and stay there, it takes a push to dislodge it from the locking lugs and the primer hole is dead center. Now i will need to put a radius back on the left side of the chamber where the sharp edge has been created from all the stoning. I will also need to throat the lead in the chamber so this barrel will accept HP's and coated lead loads. I will also do an 11 degree target crown and that should be the finish.

 

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Discussion Starter · #47 · (Edited)
It took about an hour and a half to fit the barrel like i wanted it. With the barrel locked into place and a zero lock up through the 10X match bushing now the lead of the chamber needs some breathing room. CZ's are notorious for short leads and will choke on anything not load super short or factory type FMJ's. I shoot a lot of ACME coated bullets and hollow points so the first order of business after the fitting is throating the lead. Here i am using one of Dave Manson's finest to lengthen the short lead.



I use this round for the lead length. This is a bullet meant for the .357 Sig, it has a short fat ogive and i have it loaded out to 1.140 OAL. Once this round will chamber every other round i have tried worked perfectly.



Once this round will plunk and spin i always add 2 more turns of the reamer just for insurance.

 

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Discussion Starter · #48 · (Edited)
After throating i turned my attention to the muzzle crown. Over the years i have found the 11 degree crown to be the very best for shooting cast and coated lead bullets. It is a little more forgiving with the unperfect cast bullets bases. It is also easy to see the tell tale star formed at the muzzle when the crown is cut perfectly square.




As i said before this barrel was extremely tight in the 10X bushing. This is what you want and is the recipe for match type accuracy. The problem it creates can be an issue with reliable feeding. The CZ barrels are not tapered so the bushing, when this tight, can create a lot of drag on the barrel and cause a reduction in slide speed. In order to rectify this i take about 3 thousands off of the barrel about a quarter inch behind the muzzle all the way back to the end of the chamber. This free's up the barrel and bushing in recoil but still provides a zero lock up when the slide is in full battery.




I put the radius back that was turned into a sharp corner while fitting the barrel.



Then polished the feed ramp and the radius on both sides to the entrance of the chamber.

 

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Discussion Starter · #49 · (Edited)
I will shoot some groups off the bench tomorrow to adjust the sights and check the functioning. Barring any issues i think i will call this project done after the testing.



 

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Another great transformation. For those of us with the mindset to think of the possibilities of such projects, you providing the skillset and toolset is valued and appreciated by all. I dare say you've just created a DA/SA version of what every BHP dreams of being. Kudos!
 

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Discussion Starter · #53 ·
Testing is done. We have a winner. I knew the old barrel would make a good showing although there is no good reason why it should. I warmed the new barrel up before shooting any groups with 300 hundred rounds of jacketed HP's, just to smooth out any sharp edges and kind of break it in. I then removed the new barrel and installed the freshly cleaned old one, I fouled it with a few warm up rounds and shot the group, switched barrels and shot the new barrel group. Not a huge difference but enough to make the new barrel worth installing. I waited until the sun was in the right position behind me to fully light the target before doing the groups so i could see everything clearly, limited my coffee intake this morning and tried to do everything possible to shoot these at my best. I have a new favorite favorite brown pistol i plan on enjoying for a long time. Hope you enjoyed the ride.
Group size 1.550"


Group size 1.013"
 

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Wonderful thread Shadow! Inspiring me to do some CZ restoration.....just need to find a good candidate. Would you mind posting a pic of the drill jig you used for the guide rod pilot hole?
 

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[/QUOTE]
Nice and simple, great idea, thanks for posting the pics.....have my eye on a Pre B, hopefully doesn’t go too high in the bidding. Really want to copy what you did with yours, loved the finish combined with the rosewood grips.....was looking at a pair of wooden “waffles” as a possibility. Pleased that you share your hobby so willingly, thanks again.
 

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Discussion Starter · #60 ·
I found a 12" drill bit extension at Lowes to use a regular bit and also eventually ordered the long drill bits to do this with. It takes 2 sizes depending on which guide rod you use. A 7/32" works for the poly rod or 1/4" works for all the steel guide rods. You need the extra room in the hole to get the big end of the rod around the lower lug on the barrel, the poly rod is bendable so it goes around the peanut quite easily. A drill with the 2 way bubble type level built into it is also a big help but if you take your time and make sure everything is straight you don't absolutely need this. The hard .380 plastic air line is also available from Lowes, the outside fits the spring pocket perfectly and the ID is perfect for a 7/32 drill bit.
 
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