Home | Ezine | Forums | Links | Contact
NitroExpress.com: Brno ZKK600 Project

View recent messages : 24 hours | 48 hours | 7 days | 14 days | 30 days | 60 days | More Smilies


*** Enjoy NitroExpress.com? Participate and join in. ***

Shooting & Reloading - Mausers, Big Bores and others >> Mauser Discussion Forum

Pages: 1
TilleyMan
.333 member


Reged: 23/08/05
Posts: 272
Loc: Melbourne, Australia
Brno ZKK600 Project
      #151480 - 22/01/10 10:10 PM

After all the interest in the Brno ZKK pop up peep sights, I thought I'd share a recent ZKK600 makeover project.

I had bought a cheap ZKK 600 in .270 Win (pop-up peep and the Zeiss Jena 6x32 scope!) with the view to rebarrelling to 9.3x62mm… but unexpectedly came across a mint Sako AV in that calibre, which I snapped up fast instead!



This left me with a spare ZKK600, so I after a quick crown job (ZKK's are always poor) I took it down to the range and put a packet of Remington 130gr factory loads though it to see how it performed. Although the barrel has some light pitting here and there, a good clean with Sweets and a treatment with JB paste had a best group of 5 shots into ~30mm… good enough for a hunting rifle out to 200m… so a keeper!

Since the rifle hadn't cost me too much I thought I'd see how far I could go just by reblueing the metal and reworking the stock.

One reason why late model ZKK's had problems with wandering a zero is that the 'rosewood tip' is actually part of the stock and just stained while the white line spacer is actually a U shape inletted into the fore end via a cut that nearly goes right through the timber!

There is a small ramp in the barrel channel which is supposed to give some upwards pressure to the barrel, but as the spacer is glued into the stock, over time the glue fails and the entire fore end tip is free to flex wherever it likes. I sawed the rest of the way through the factory tip then dowelled and fitted a proper contrasting fore end tip. A standard grip cap from Brownells replaced the rather gaudy 'rosewood' grip cap, and blued to match the barrel.



Existing checkering recut:




I unsoldered the original barrel band foresight ramp and fitted a Recknagel QD barrel band, cleaned up the barrel and re-attached the foresight after cleaning up the profile with small files and wet and dry paper down to 400 grit.

I then turned my attention to cleaning up the receiver and bolt…
Feedramps were cleaned up with a Dremel, then polished.
The receiver rails were stoned smooth, then lapped into the bolt body using fine valve grinding paste, the end result was very smooth travel indeed.

Many ZKK's suffered from poor quality surfaces esp around the LHS lightening cuts after factory cutting with poorly maintained profiling tools… this took a lot of time and effort with diamond files and stoning but was worth it!



The ejector plate was removed and small burrs cleaned off to slick up the travel (again worth checking for burrs as this can cause inconsistent ejection). The receiver was then masked and bead blasted to match the factory finish. The bolt was then stripped (using the nifty disassembly tool supplied with every rifle) cleaned and polished, again down to 400 grit.

The trigger guard and magazine floor plate had some quite deep scores and took a lot of time to clean up.

The trigger pull adjuster set screw was found to be stripped, so the thread was cleaned up with a button die, with the corresponding hole in the receiver retapped.



This screw is often found to be stripped on ZKK's as the unsuspecting owner tries to adjust the terribly creepy standard trigger pull.

If adjusted too far in it drops out of the threaded hole, but spring pressure makes it cant over… if the screw is reversed carelessly, it will start in the threads offcentre and then strip and bind halfway up as the hapless owner cranks on the screwdriver.

I'm not a fan of the ZKK set trigger, it can be adjusted and stoned to give a good release when set… but is always dreadfully vague and creepy when used unset.

It is also rather noisy… the sharp CLICK when setting will alert game.
Just replacing the set trigger with the standard trigger won't improve things much either… the pivot pin need to be replaced with a larger diameter one to remove axial play (I just measure the diameter of the standard pivot pin with a micrometer, then use an imperial, or a number/letter drill cutoff at the shank to give a slightly tighter fractional fit) the standard sear engagement is usually around 1.5mm… WAY too much, so it needs to be carefully ground back , then all surfaces stoned for a crisp release of ~3lb.

The safety has a rubber buffer block, which gradually dissolves (under the influence of 30+years of oils or solvents) into black goo that spreads though the safety recess and then hardens. This always needs to be checked on any second hand ZKK, as it can cause the safety to not engage correctly.

Anyway… it was an interesting and satisfying project.. hope you enjoy the results!







Post Extras: Print Post   Remind Me!   Notify Moderator  
CHAPUISARMES
.416 member


Reged: 16/01/08
Posts: 2908
Loc: DUBBO, NSW, AUSTRALIA
Re: Brno ZKK600 Project [Re: TilleyMan]
      #151481 - 22/01/10 10:19 PM


Hi Tilleyman,

What a difference, you would not think it was the same rifle, after that it sure is a "Keeper"

Cheers,

Jeff Gray

--------------------


"Travel Light, Travel Fast and carry a Big Bore"


Post Extras: Print Post   Remind Me!   Notify Moderator  
tophet1
.400 member


Reged: 15/09/07
Posts: 1873
Loc: NSW, Australia
Re: Brno ZKK600 Project [Re: CHAPUISARMES]
      #151485 - 22/01/10 10:34 PM

Mate,

What a great job you did. With that 270 and your 9.3x62 you have an excellent world class hunting combination.


Post Extras: Print Post   Remind Me!   Notify Moderator  
FATBOY404
.400 member


Reged: 14/11/09
Posts: 1730
Loc: QLD
Re: Brno ZKK600 Project [Re: tophet1]
      #151490 - 22/01/10 11:16 PM

It is a credit to you. Well done.

--------------------
"WHATEVER BLOWS YOUR HAIR BACK"


Post Extras: Print Post   Remind Me!   Notify Moderator  
JACKEL
.275 member


Reged: 12/01/10
Posts: 52
Loc: BUENOS AIRES, ARGENTINA
Re: Brno ZKK600 Project [Re: FATBOY404]
      #151494 - 23/01/10 12:39 AM

Beatiful !!! thats a really nice work I love how that rifle looks now, Any chance you post a picture of the new barrel band please.




Best reagards.



Ernesto.


Post Extras: Print Post   Remind Me!   Notify Moderator  
GK
.300 member


Reged: 29/10/09
Posts: 161
Loc: Adelaide
Re: Brno ZKK600 Project [Re: JACKEL]
      #151496 - 23/01/10 12:58 AM

Fantastic effort, you are obviously a very capable craftsman. I would love to have the patience to undertake such a refurb.
What was the stock finish that you used and what was the brand of recoil pad?
Also you mentioned that the trigger had 1.5mm engagement but what did you reduce it down to?
Regards
George


Post Extras: Print Post   Remind Me!   Notify Moderator  
xausa
.400 member


Reged: 07/03/07
Posts: 2037
Loc: Tennessee, USA
Re: Brno ZKK600 Project [Re: TilleyMan]
      #151516 - 23/01/10 04:34 AM

Maybe there should be a new category called "Silk Purses From Sows' Ears". This transformation would certainly qualify.

The only improvement I can think of is in the safety department: a nice Model 70 three position safety would make the rifle a real pleasure to use in addition to being a joy to behold.

When I bought my ZKK 602 back in the early 70's, it was with the prospect of a hunt for driven wild boar. I practiced and practiced with the safety, trying to overcome my natural inclination to push the lever forward to release it. When the time came and I was safely ensconced at my stand, I decided to go ahead and take the safety off, in case I got a sudden opportunity for a shot. After a while, two yearling pigs (Ueberlaeufer) ran across my front. I threw up my rifle, AND PUSHED THE SAFETY FORWARD. There's no teaching even a comparatively young dog new tricks.


Post Extras: Print Post   Remind Me!   Notify Moderator  
FATBOY404
.400 member


Reged: 14/11/09
Posts: 1730
Loc: QLD
Re: Brno ZKK600 Project [Re: xausa]
      #151523 - 23/01/10 05:41 AM

As a left hander (when shooting) I like the Brno safty as it is under my left thumb.
You just have to think it as a hammer on a 30-30, pull back to cock !.

--------------------
"WHATEVER BLOWS YOUR HAIR BACK"


Post Extras: Print Post   Remind Me!   Notify Moderator  
4seventy
Sponsor


Reged: 07/05/03
Posts: 2210
Loc: Queensland Australia
Re: Brno ZKK600 Project [Re: TilleyMan]
      #151556 - 23/01/10 12:36 PM

Nice job!

Post Extras: Print Post   Remind Me!   Notify Moderator  
TilleyMan
.333 member


Reged: 23/08/05
Posts: 272
Loc: Melbourne, Australia
Re: Brno ZKK600 Project [Re: 4seventy]
      #151560 - 23/01/10 03:06 PM

Thanks guys

Ernesto
Sure happy to take some more shots of the barrel band area when I return home.

GK
The stock was finished with 15 coats of Tru Oil, first few coats wetsanded with 400 wet&dry then wetsanded with 800 every third coat and 1200 on the last few. Then handrubbed with pumice for a satin finish.

The recoil pad is a standard Pachmayer 'Old English' Medium size.

I reduced the sear engagement to about 0.5mm didn't want to go down too far for safety, so it still has a very small amount of creep but won't jar off no matter how many times I pound the butt pad into the lino. Each rifle is different.

BTW
This is a photo of the two types of standard trigger fitted to the ZKK... note the shorter upper tang for the 600/601 vs the 602 on the RHS.






Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1



Extra information
0 registered and 10 anonymous users are browsing this forum.

Moderator:  NitroX 

Print Topic

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Topic views: 27565

Rate this topic

Jump to

Contact Us NitroExpress.com

Powered by UBB.threads™ 6.5.5


Home | Ezine | Forums | Links | Contact


Copyright 2003 to 2011 - all rights reserved