PDA

View Full Version : CZ 452 makeover.....................



CYanchycki
02-03-2008, 05:36 PM
My factory CZ 452 shoots just as well as many expect them out of the box. I decided that it must have a makeover. This is something that I want to do and a lot of people are wondering about the final outcome. So here is what I have done and there is some advice I am looking for. It will never be a Anschutz, Feinwerkbau, Win 52, 40X or any of the custom aftermarket rimfires but that is ok. I know it will never be as competitve as one of the previously mentioned but it must be done.

I have a Don Stith pepper laminate stock on its way up. It is coming with his trigger guard which he has had fabricated.

http://i3.photobucket.com/albums/y94/cycbb486/DSCN9944.jpg

I have installed an adjustable sear. Polished the trigger contact surface and installed a Eric Brooks spring on the trigger as well. It is the lightest that comes in his kit. Tested on a scale it averages at 7 oz. For as simple a design the trigger is it is pretty crisp.

A new barrel is on order. It is a Benchmark 6 groove 16.5 twist in a reverse taper. It should finish at 25" and the muzzle be around the .910-.920 diameter. The shank is going to start at a 1.100". The diameter of the action is around 1.180". I figure this way the face of the receiver can be made true and a shoulder put on the shank of the barrel.

I spent some time on Friday with my 10 year old daughter in front of the tv watching Shrek 3. I love kid movies. :eek::D While doing that I lapped the bolt with Flitz. The bolt did not slide that smoothly in the receiver nor close very smoothly. When all was said and done it was 100 times better. I also polished the firing pin and did a slight modification to the angle of the firing pin in how it contacts the rim. I sanded and polished down the edges so that it would engage the inner edge of the rim B4 the outer. Taking a page out of Calfee's reads. It is just a firing pin that is easy to replace.

I also took one afternoon while I was off with the help of my doctor ;) to fabricate a larger bolt handle. I am no gunsmith or make myself to be one but I like trying to butcher things. I hacked, angle grinded, and bench grinded the factory ball end off and threaded it to 10x28.

http://i3.photobucket.com/albums/y94/cycbb486/czbolt2.jpg

Made my own creation out of 1/2" aluminium rod, drill press, dremel, and sandpaper.

http://i3.photobucket.com/albums/y94/cycbb486/2008_0117Image0029.jpg

Not bad butchering job I thought for the high tech lathe equipment I used.:D

Scope rings are an issue for the 3/8 dovetail but I decided on a set of BKL rings in silver. They are cheap and look well made. I could not find anything else.

Ok, this is where you fellows come in. I want some advice on changing the mounting system of the receiver to the stock.

If any of you are familiar with the CZ 452 American, it has a bolt that goes thru the stock and into the receiver between the sear and the plastic magazine acceptor(I just bought this gun this spring) so yours may not be plastic. The second bolt goes thru the stock and is attached to the barrel. The barrel has a dovetail cut in it and a threaded bushing slid into it where the bolt attaches. Since I bedded the factory stock I did away with that attachment. From what I can see it sits rock solid with just the one bolt and fully freefloated. It shot great B4 bedding and great after so I know I did not mess it up.

Here are some pics to help you see what I am wondering.

Pic 1

This is the receiver as it is out of the stock with all in place except for the dovetail bushing for the barrel. The hole between the sear and the mag acceptor screw is where the bolt goes that attaches it to the stock.

http://i3.photobucket.com/albums/y94/cycbb486/2008_0203Image0020.jpg

I am doing this build as a single shot so the mag acceptor will not be utilized. It will look like this.

http://i3.photobucket.com/albums/y94/cycbb486/2008_0203Image0024.jpg

As you can see the small flathead screw is still required because there is a small piece of metal that is held in place by it on the inside of the receiver. That metal sits on siderails on the inside as well as there is a notch milled on the underside of the barrel that the front of it slides into. That metal has a small protrusion at the rear end of it that kicks the spent casing out of the port opening. Here is a picture with the parts sitting in what would be there respective places.

http://i3.photobucket.com/albums/y94/cycbb486/2008_0203Image0022.jpg

The silver looking piece above the receiver is the metal piece that goes inside the receiver. You can see a slight protrusion out the front of it that slides into the milled cutout on the bottom of the barrel. It fits between the barrel and the receiver.

To avoid milling the new barrel I feel the protrusion can be removed. There is support from the underside by the side rails of the receiver and the one screw that holds it in place. It must stay there because the bolt rides along the surface of it.

Sound good so far?

The thing I am now wondering about is putting a second attachment for the receiver to the stock. The new barrel will be heavier and I may end up with a tuner on it as well.

If you look at picture 2 there is the now front empty hole that used to have the screw that held the mag acceptor. It is not going to be used as I am doing it as a single shot build. My plan is to have that hole retapped to a standard thread pitch of 10X28. This can be used as the second attachment point along with the existing bolt between the sear and small flathead screw.

Sound OK?

Well someone gave me another idea that I was going to do. The thought was why not do as I planned for the front bolt but drill and tap the rear tang for the second bolt eliminating the center one completely. Sounded great to me until someone advised to not do it. I thought hey easier to bed and a wider footprint for stability doing it that way. Problems I was advised about were, there is not a lot of metal in the rear tang area maybe enough for a couple of threads and I could possibly induce more stress into the receiver by bedding it that way. I was advised to just stick with the center bolt and the front bolt. It is quite simple to put a pillar for the front bolt but a little more work for the center. The pillar has to be milled to fit in that tight spot. It can be done as I have done it on the factory stock. Doing it in that manner I was told would be similar to the Anschutz. When bedding the action I was told I should freefloat from the center action back.

What I want to know is how should I tackle the mounting job and bedding of the receiver to the stock?

How about the extractors would you recut the grooves in the new barrel or go with a reverse cone at the chamber end?

I would like your opinions.

Again, I realize this is no BR action but I must see this thru. If it ends up not shooting at least it may look good in the end and I will have learned my lesson.

Calvin

CHRIS.T
02-03-2008, 06:40 PM
CYanchycki,good build up and story,interested to see it finnished.

Regards Chris.

bohunk
02-03-2008, 07:40 PM
Calvin,
Sounds like you've got a pretty good project planned. If it was me...I'd go with using the existing mounting screw and use the front magazine hole like you talk about doing. Most people bed to the front of the receiver and free float the entire barrel.
What governing body do you plan shooting under. If you want to make a 10.5 pound gun you may have a bit of trouble making weight with the barrel dementions you'll be using and the Stith stock. I'm not saying it can't be done, but it might be tough. If you plan on shooting ARA you're home free.
Good luck and keep us updated as you progress.

fishin'fever
02-03-2008, 08:47 PM
First let me say that if you can read wind flags,know how to tune with good ammo,your CZ will be very competive.I built one for myself and love it,also one for my doughter. I used a Benchmark barrel,straight no taper.I used a cone breach.I added a piece of steel to the tang and drilled and tapped it.I bedded complete action.I took second place in the Wawarsing ARA championship match also the high target 2350 with this rifle.Hope this info. helps you! Good luck! Marty

dkwflight
02-03-2008, 09:08 PM
Hi
Look into the screw in the rear of the trigger gaurd. It seems to line up well with the reat of the receiver. I have been thinking about putting one there.
I also have been thinking about one of the Lija barrels that have been discussed here.

I did run into a discussion of beding the 452 some where. I can't think of where now. They used a thick resin like JB weld so it would not run all over. The discussed using a brass threaded insert around the screws. They said they used a part from the lamp repair department of the local hardware store.
Dennis

CYanchycki
02-03-2008, 10:13 PM
which governing body will I shoot under, the governing body of myslf.;)

I am unaware of any rimfire benchrest shooting in Canada. As a matter of fact I live in the wrong country and province when it comes to owning and shooting a firearm.:( It REALLY SUCKS. There is something about competitive accuracy in Canada that people appear to be scared of. I am doing this solely for myself just as I have built my PPC for myself. The costs involved with travelling to learn the accuracy game, shoot, and meet people are not within my budget. I do it solely for my own enjoyment.

Maybe when I have the opportunity to retire and have enough money set aside I may be able to pursue that dream.:(

Leeroy
02-04-2008, 06:35 AM
G'day Calvin

Nice looking job so far mate!:D

I have a similar project on the go at the moment, (well actualy on the backburner). But just thought you might be interested.

Here are a few shots of how i solved the mounting screw in the tang area.

A shaped block of 4140 was tig welded to the underside of the receiver then drilled and tapped. The second tapped hole is for my own design 3 sear/leaver trigger. The drawings have been done for the trigger but no work started yet.
I didn't use the middle screw for all the reasons you stated. The front screw is the old Mag mount screw hole opened out to M6. I also setup and surface ground the top(or bottom) of the rear mounting lug and the front flat on the underside of the receiver, for a dead flat area for pillar bedding.

I have also included a shot of my single shot magazine follower. I made this from a peice of 4140 round bar. It works realy well, no more having to fit my large fingers into the chamber area to start a round. Just drop one onto the plate and close the bolt, easy..

Hope that helps..


Cheers Leeroy

Douglas
02-04-2008, 07:03 AM
Leeroy, were you at all concerned about warping the receiver when you made the TIG welds? It looks like you only did a small weld front and back, more than enough to hold the block in place, but I wonder about the heat required to make the welds? Thanks, Douglas

Leeroy
02-04-2008, 07:16 AM
G'day Douglas.

Welding it didn't realy worry me to much. The tig welding was done a little at a time so not to much heat input, and allthough it is actualy fully welded all the way arround there was no signifigant distortion. Besides that, the welded part is well behind the bolt bearing area in the receiver body.
The action was also trued (Blueprinted) after the welding process..

Cheers
Leeroy

CYanchycki
02-04-2008, 08:01 AM
you are a little more adventurous than I am. If I knew enough about welding and the properties of metal it may be something I would tackle. Since I don't I think that is one part I will pass on. To have it done at a shop is something I would not trust and the cost t odo a specialty job. It is a small piddley job.

I like the single shot adapter. Again, if I were able to mill my own it would be great. I did mill my own out of 3/4" Delrin, drill press, hacksaw, and sandpaper. It friction fits in the existing slot and works like a charm. A few dabs of Marine Tex and it is there to stay if required.

Thanks for the input and keep it coming.


Calvin

CYanchycki
03-08-2008, 10:46 AM
gathered up for the build and it should be at the Gunsmiths on Vancouver Island Monday.

It is the budget project but I am very curious as to how it will all turn out.:confused:


Calvin

Jetmugg
03-08-2008, 11:18 AM
I'm another one who has welded a lug to the rear tang of a CZ 452 action. I have a 452 Varmint. Are you sure yours is an American? I thougth that the American models used a rear lug dovetailed to the tang and the "mid" action screw location.

Anyway, I removed the front barrel lug, reshaped it slightly to match the radius of the rear tang area, and welded it to the underside of the rear tang. This location lines up perfectly with the rear triggerguard screw. I then bought the correct flat head socket head bolts, and "voila", I have a CZ 452 Varmint whose barreled action is mounted to the stock more solidly.

I don't know if the rifle actually shoots any better, but I feel better about it. (This rifle is used mainly for SB Silhouette, but I might try it at one of the local BR matches just for fun.)

SteveM.

_Shorty
03-08-2008, 02:51 PM
The 452 American and the 453 Varmint both use the rear and middle trigger guard screw holes to mount the action to the stock, so, yeah, that'd be the logical place to put one if you're going to do that to the 452 Varmint. You'd think that getting rid of the screw in the barrel would help in the accuracy department. At the very least, you'd think the screw in the barrel would be very sensitive to torque in affecting accuracy. Whether it is or not, I don't know. But I'd probably want to do what you did with yours and move the mounting screw to the rear like that if I had a 452 Varmint. It was actually one of the reasons I chose the 453 Varmint instead. The trigger being the other reason.

bj bostic
03-08-2008, 05:20 PM
I have 3 czs built to shot benchrest. That is not an american all americans have a rear dovetail bolt and 1 between the trigger and clip assembly that way when you put on a new stock you only haft to use the rear. But id use a target chamber with the cz as long as you dont dry fire it there great. Have you thought about piller bedding it.

_Shorty
03-08-2008, 10:43 PM
CZ designed their bolt and firing pin such that it is safe to dry fire, as the pin doesn't reach the breech face of the barrel and won't contact it. Someone on rimfire central received word back from CZ stating that they don't see any reason to recommend against dry firing their rifles, and the manual for them also states that you should dry fire it before storing the rifle so you don't leave the spring under tension. They don't see how any damage would occur, and if any did it would be covered by warranty, but they've never had to do any warranty work from this. Just wondering why you might say not to dry fire them?

CYanchycki
03-08-2008, 10:56 PM
any problem with dry firing them. Mine has been dry fired hundreds of times and I see no hint of the firing pin touching the barrel face.

Ok and yes you guys are right it is not a true American it is the Varmint. According to the CZ Website the 452 Varmint is the same as the American accept for the difference in the barrel. As I have not seen the American I cannot tell you otherwise.

Regardless, the project will be what it is.

Will there be any welding done? Not a chance. The man doing the building used to play with the BRNO's about 40 years ago and no welding was done then so there will be no welding today. I have faith in what he will do for me thru our discissions. He may not have the reputation of the top gunsmiths in the US but he studied gunsmithing as a young man and has been accurizing and building guns for about 40 years.;) That is enough for me.:D

_Shorty
03-08-2008, 11:05 PM
Which is why I'm happy he's not even a 2-hour drive from me. :)

Kim Cosstick
03-09-2008, 03:23 AM
Leeroy
I like the single shot adapter. Could you show me more detail of the top side where the bullet sits. Or give me a drawing with rough dimentions.
I also have a BRNO with a round disc welded onto the tang and if you bed it right it acts as a recoil lug.

bj bostic
03-09-2008, 03:43 AM
Thats fine if you use a factory chamber that comes with the rifel but if change it to a target chamber with the rim out when you dry fire itit burrs the side of the rim which makes it hard to but a shell in and eject one out

_Shorty
03-09-2008, 03:45 AM
You don't need to use an empty case to dry fire. It is impossible for the firing pin to touch the breech face of the barrel.

edit - Take your bolt apart, you'll see why. CZ says it is safe, and I believe them, and I believe the evidence I see when I have my bolt apart.

Mr. D
03-09-2008, 04:29 AM
Not to argue, but to inquire:

(1.) What standard of accuracy do benchresters use when they state that a CZ could not approach the accuracy of the more popular benchrest rimfires (Anschutz, etc.)?

(2.) Are there any benchrest quality 17 HMR cartridges. I find 17 HMR to be like a 22 LR high velocity, hollow point, that is, not very consistent in terms of priming. Am I right in this observation?

CYanchycki
03-09-2008, 08:44 AM
I would probably say the same reasons why for the CZ as a Rem 700 Centerfire to a BR match versus a custom build. It will get you there but when you seperate the men from the boys you will be with the boys. Some may be happy just being in the group with the boys but others...............

You have to admit some of the internal receiver maching is quite crude looking. The trigger is functional but not like a Jewell, Kelby, or Rem which are quite easily adjustable but basically drop in and shoot.

What makes them good factory shooters has all got to be in the barrel?????

Mr. D
03-11-2008, 07:06 AM
I would expect what you said to be true, but what kind of groups do custom barrels and Annies shoot so I have a comparison to my cheapy CZ 453?

I'm shooting a 17 HMR and frankly it seems the ammo is the weak link as to consistency in group size. I've shot .166" at 50 meters, but every once an awhile a shot pops out of the group when the hold felt solid. I also get a misfire about every 250 rounds with a heavy firing pin hit. I think the priming is suspect on 17 HMR ammo. I guess that's why benchresters pay alllot for their ammo! :D

_Shorty
03-11-2008, 07:13 AM
I don't think there's much going on for .17 HMR as far as benchrest goes, and the ammo is more or less just hunting ammo as a result. They can be very accurate, but aren't always, as you've seen. You'll need to go to .22 LR for widespread benchrest support, which includes the availability better ammo.

Mr. D
03-11-2008, 05:23 PM
Shorty,

Well, I payed $8.60 for 50 rounds of 17 HMR, so I guess I can't expect benchrest quality priming! :rolleyes: Ground squirrels need more speed that 22 LR it seems! :D

CYanchycki
04-30-2008, 07:57 PM
It is presently about just over 1 week away from completion. I have some pics from this AM from Dennis after sitting overnight in the first stage of bedding.

After bedding is complete the trigger shoe needs to be bent forward to fit properly in the trigger guard and the final finish put on the barrel.

All I will have to do is make and install a aluminium buttplate and finish the stock. I am going to make one modification to the stock B4 it is finished. I plan on angling the sqare back of the forend. I will knock the corners off at a 45 and blend it in.

http://i3.photobucket.com/albums/y94/cycbb486/22CZ2.jpg

http://i3.photobucket.com/albums/y94/cycbb486/22CZ1.jpg


Calvin

1bamashooter
04-30-2008, 10:40 PM
I'm using a factory CZ 452 American for a sporter in IR 50/50 3 gun with a 6 power Redfield This rifle IS the absolute most accurate factory sporter I have ever seen, it will shoot tiny 5 shot groups at 50 yds with Lapua Master M. If yours is anything like mine you will have a shooter. Post a range report after you get to the range.

CYanchycki
05-15-2008, 06:05 PM
a bit of waiting the project is in my hands. Thanks to Dennis Sorensen aka Guntech for the great work.

Here it is.

http://i3.photobucket.com/albums/y94/cycbb486/2008_0515Image0024.jpg

http://i3.photobucket.com/albums/y94/cycbb486/2008_0515Image0025.jpg

http://i3.photobucket.com/albums/y94/cycbb486/2008_0515Image0026.jpg

All that is left is to make the aluminium butt plate and complete the Import paperwork for a new Weaver 36X in silver for it.

If things go as planned I may make it to the range to try it out.


Calvin

fyrechaser
05-15-2008, 06:46 PM
BEAUTIFUL!

Looking forward to a range report on this one!


Jim B.

Butch Lambert
05-16-2008, 09:38 AM
Calvin,
You have a PM.
Butch

CYanchycki
05-17-2008, 10:27 AM
Looking forward to a range report on this one!


Jim B.

will a CZ 452 with a Benchmark reverse taper barrel, chambered with a match reamer shoot? I definately think so.

I went out this morning to give it a shot. I was not really sure why because the winds were 30 kmh with gusts to 45 kmh. Took some flags and set up at 50 yards. Target was a USBR practice target printed off of the net on 60lb paper.

I started with a bore just cleaned from the other night with some kroil on a patch and dried it out. Pulled a box of Lapua Master M out gave it a shot.
The first shot printed in the 6 ring about 1 o'clock. The next 4 printed in a beautiful 4 shot group (basically 1 hole) at the 3 o'clock position disected almost perfectly by the 6/7 ring.

After that, things went for ****. The wind picked up fast and started to switch like crazy. Regardless, I was very happy with my amateur wind reading skills. I could pretty much tell when I was loosing shots out of the groups. I could just not find a condition that would really come back and repeat itself predictably. If it was close the velocity was down. I did not try to compensate for the lower velocity. I wanted to see the effects of the wind pushing the bullets around.

This shooting in the wind gives me a real respect for the guys and gals that can shoot well in it.

I will keep you posted when I get a day that the wind is down where I feel that I can confidently give a better assesment.

Until later,
Calvin

brad541thb
05-17-2008, 04:41 PM
Calvin,

Nice rifle. You will love that Benchmark barrel. Keep us up-to-date on the results.

takdriver
08-17-2009, 08:16 AM
a bit of waiting the project is in my hands. Thanks to Dennis Sorensen aka Guntech for the great work.

Here it is.

http://i3.photobucket.com/albums/y94/cycbb486/2008_0515Image0024.jpg

http://i3.photobucket.com/albums/y94/cycbb486/2008_0515Image0025.jpg

http://i3.photobucket.com/albums/y94/cycbb486/2008_0515Image0026.jpg

All that is left is to make the aluminium butt plate and complete the Import paperwork for a new Weaver 36X in silver for it.

If things go as planned I may make it to the range to try it out.


Calvin

what kind of stock is that? and how many action screws does the 452 have?

Escbowhunt
08-20-2009, 10:03 PM
That is a Don Stith Stock, That action from the factory has 1 action screw I think he was trying to add another using the front mag well screw hole.

_Shorty
08-20-2009, 10:18 PM
The 452 has a few variants, some with 2 actions screws, and some with 1 action screw and a barrel lug/screw. The 452/453 American has two action screws, as does the 453 Varmint. The rest slip my mind at the moment, but you can check rimfirecentral for lots of CZ info.

CYanchycki
08-20-2009, 10:47 PM
it is a Stith stock.

In regards to action screws this model had the one screw in the action and the other in the recoil lug dovetailed into the barrel.

I had the gunsmith that put it together drill and tap the rear tang for another screw. The metal in that area is not very thick but there is enough there to make a functional attachment.

Calvin

Escbowhunt
08-21-2009, 01:03 AM
I got the stock right.

Are those rings the lows or highs?
And have you you been shooting that thing Calvin?

Theron

CYanchycki
08-21-2009, 07:39 AM
are just the standard BKL rings.

Do I get out shooting it much? Not very often.

Maybe after Sept. long weekend which is my last center fire match I may dust it off and have at it. After having it put together and shooting it somewhat I just realized that I do not get the same satisfaction shooting rimfire as I do centerfire.

I do have a couple last things to finish it off. Put some weight in the butt and get a tuner for it.

Calvin

takdriver
08-21-2009, 08:34 AM
are just the standard BKL rings.

Do I get out shooting it much? Not very often.

Maybe after Sept. long weekend which is my last center fire match I may dust it off and have at it. After having it put together and shooting it somewhat I just realized that I do not get the same satisfaction shooting rimfire as I do centerfire.

I do have a couple last things to finish it off. Put some weight in the butt and get a tuner for it.

Calvin

What kind of groups are you getting at 50 yds?

-------------------------
http://www.takdriver.com

CYanchycki
08-21-2009, 08:47 AM
be honest with you I have not given an honest effort to evaluate the rifle.

I do have plenty of top end Eley Tenex both the old a new generics to try as well as some Lapua.

It was chambered for Lapua ammo and the limited testing I did Lapua was the bullet of choice. Fortunate enough I have a dealer with Lapua ammo in my hometown to pickup and try the Midas. The Master M I have shoots quite well in it.

It has hovered for me in the high 2's low 3's.

Like I said I have not given it a honest effort as of yet. Just going by memory. I am lucky if I have fired 300 rounds down the pipe as yet.

Calvin

takdriver
08-21-2009, 09:20 AM
What kind of barrel do you have on there?

-------------------------
http://www.takdriver.com



be honest with you I have not given an honest effort to evaluate the rifle.

I do have plenty of top end Eley Tenex both the old a new generics to try as well as some Lapua.

It was chambered for Lapua ammo and the limited testing I did Lapua was the bullet of choice. Fortunate enough I have a dealer with Lapua ammo in my hometown to pickup and try the Midas. The Master M I have shoots quite well in it.

It has hovered for me in the high 2's low 3's.

Like I said I have not given it a honest effort as of yet. Just going by memory. I am lucky if I have fired 300 rounds down the pipe as yet.

Calvin

CYanchycki
08-21-2009, 09:34 AM
16.5 twist reverse taper.