CZ 452 Benchrest Customisation

Part 1

The trigger has been using the Eric Brooks trigger kit. I had this trigger kit already on the rifle but I managed to get time to lower the trigger pull to about 1lb. The kit can be obtained from Eric Brooks directly at his new web address at http://www.cz452.com/ It is relatively easy to install and he supplies online instructions you can follow easily. There is a safety warning, so be aware of this. The kit comes with four springs and two collate like sleeves for the trigger and sear respectively. You can choose the weight of trigger pull by combining the springs with the two thicknesses of collate. As my rifle is meant for Benchrest I went for one of the lower trigger pulls. When set it comes out very clean and crisp with little or no creep in the trigger pull. Eric also does hex action screws, inch pound torque screwdrivers cleaning rod guides (which I hope to try out) and a host of other CZ goodies. The website is well worth a look. I bought new hex action screws a while ago to ensure I get accurate torque each time I disassemble the rifle, using a set torque screwdriver fixed at 20lb f in, which is a common setting for the CZ rifle with barrel lug. More can be found on torque settings on Eric Brooks website. To achieve consistent accuracy with your rifle it is well worth reading. Alternatively you can get the trigger kit from Roger Francis at South Yorkshire Shooting who imports Erics products directly at; http://www.rimfiremagic.co.uk/ . I think most of the CZ rifles he sells go out with this trigger kit already installed

I also made a set screw to try out for the barrel lug on the varmint. This retains the lug in a fixed position so it does not move. (Do be careful when tightening this as with lighter/ thinner barrels it could distort the barrel and rifling. It does not need to be too tight. If unsure leave it.) The CZ 452 does differ in design from one model to another, some actions having a barrel lug with a retaining bolt, plus one action screw. Others, like the American, have two action screws. The Varmint model has the former design and there is much debate over the usefulness of the barrel lug, (some throw it away just relying on the one action screw). Having read a bit about bedding I believe the barrel lug works well, as it acts like a basic pillar bed on the barrel. If you read the article at http://riflestocks.tripod.com/ things make sense as the barrel should be bedded in some way up to the balance point of the action and barrel. The barrel lug does this in part. There are various articles on the web and rimfire central on this theme and it is worth taking a look before you start overhauling your rifle. You need to decide for yourself what method you will use. After talking to Eric Brooks, who is the US guru for CZ rimfire rifles, I

Set screw

Sear Collate/ sleeve

Trigger Spring

did a bit of reflection. I asked if the barrel lug should be removed. Although he does not favour the barrel lug design, as it can give rise to inconsistent reassembly, he recommends setting it in the way described. However, do experiment with the torque applied when setting the action and screws back in place. (Remember CZ usually set the action screws between 20 and 24 f in). Bedding the action into the stock is part of this process and I will get around to that when the stock arrives. I have some parts ready for this which I will deal with in a later article. Next I hope to get the bolt jewelled, as I have been experimenting with patterns over the last month. (I did manage to prepare the bolt by polishing to a near mirror sheen).

Before/ After

It is time now to bite the bullet, not literally, and get on with it. Bill Shehane has started to make my stock, so I hope this will be with me in next month to six weeks. Once that is with me I can finished the lacquer on the wood and begin bedding the rifle. His stocks can be found at; http://www.scopeusout.com/ I also hope to get the extension of the bolt arm started, but we will see how long the above takes me.

Part 2 Quite a few things have spurred me on with the next part of the project. Not least the arrival of the Shehane Tracker stock, which is a thing to behold. Anyway more of that at another time. I will have to wait to bed the action and finish the stock as I am still waiting for parts to convert the CZ to single shot only. (The part is from the Walther KK100 target rifle, which uses the same receiver as the CZ 452). The bolt jewelling went well, all be it the pattern turned out slightly different to what I wanted. Instead of going into details here about how it is done, the following website has ample instruction. http://www272.pair.com/stevewag/jb/jb.html

I suggest using a very abrasive compound on steel, about 120 grit. For a finer finish like mine 400 to 600 grit. It depends what you want? The Brownells brushes shown in the web article can be bought from any hardware shop, including B&Q, for between £2.50 and £4. With the bolt suitably polished and cleaned the next part for the equation was the make an extended bolt arm. Two reasons for this; One, the CZ bolt knob is very close to the wood work and hard to grip from a bench

position. It does not protrude out for an easy grip. Two, I wanted more leverage when working the bolt, to try and reduce movement between shots. Firstly the original knob has to be removed. Do look at the amount of metal you are leaving yourself to put a thread on the metal that is left. The part of the arm that is left will vary from rifle to rifle, but the smallest diameter on mine was 5mm, which is ample to turn a thread. (It actually varied from 7mm to 5mm, thus some filing was necessary to form a round of 5mm. If you wish you could build up the metal to 7mm by using a mig welder, but protect the rest of the bolt from splatter if you take this route). The new bolt knob has been turned from aircraft grade aluminium, as I love this metal as it gives a great finish. The design is similar to some Italian ones I have seen and liked in the past. Both bolt knob and arm had 5mm threads turned using a tap and die; the knob whilst still on the lathe to ensure a straight thread was cut. When all cutting has been done, finishing the bolt arm and knob with silicon carbide cloth is a must to get a fine finish. The steel arm needs 200 to 400 grit to accept new bluing, whilst the aluminium needs 600 to 800 grit. After bluing the steel both are then married together using a thread lock adhesive; I used the medium strength adhesive just in case I want to change at a later date. After all polishing and finishing I was very happy with this part of the conversion. The handle is now about 115 degrees from the vertical , giving a much better grip and access to work the bolt.

Lastly, for this session, I decided to adapt a BSA Martini trigger shoe to give a better feel to the CZ trigger. The original is hard to feel at times and I wanted something better. The shoe was shaped to fit the profile of the CZ trigger better, using an epoxy putty to mould the shape of the trigger to the shoe. The putty is very strong and takes the shape of both easily. This was them reduced and finished with a sparing amount of aluminium black. (This was also used on the bolt arm extension). Aluminium black is best sealed using clear enamel, acrylic varnish or gun stock oil. Next time I hope to report on the stock or the new trigger guard I want to make. So far can I say many thanks to Bill Shehane for an excellent product, Eric Brooks for his support and not least Vince who has answered all my questions and best of all made me think.

Part 3

At the time of writing most of the furniture for the new rifle is now done. I have a few bits to finish off, but these are minor and next stage is the final one of bedding the rifle and fitting everything together. However, let’s get back to how far I have come thus far! One of the things I have found, like most, is when you get good service keep going back to the place you get it. Try as I might to get one part for the rifle refit, a new single shot shell plate, I could not. I forgot that a local supplier I use a lot did business with Walther. Why Walther when I am developing a CZ 452? Well the Walther KK100 prone rifle uses the same receiver as the CZ 452. BRNO even makes it for Walther, who add a new trigger, barrel, etc. Therefore everything that fits the KK100 receiver will fit the CZ 452 receiver, with a little adaptation. (This includes the far superior trigger they have on the KK100, but check all this out for yourself first and it costs!) Anyway, after having a chat with John and Bill from Churchley brothers, they asked me to leave the request with them for a week or so, as I had tried literally everywhere else (and had the wrong piece sent), including Walther themselves. Within a week Bill telephoned me to say they had got it – amazing! Now that is support from your local gun shop and Churchley's will get most things you need for rimfire. Many thanks to them! Once obtained the new metal shell plate was fitted. but this did involve pinning to the receiver, so you may want to get a gunsmith to do this for you. This new adaptation has a spring at the base which lifts the .22 round to the breech allowing the bolt to squarely insert the round into the breech.

Much better that the plastic single shot magazine adapter we get over here! This also promotes the fact that this rifle will be single shot only, so a magazine well does not have to be taken out of the stock. With this bit finished, and after getting hold of an aluminium billet via a friend at my club, I started on the new trigger guard. This can be made in a variety of ways, CNC milling, manual milling or crafted by hand. I went for the latter method to see if I could do it. This took a lot of cutting filing and reducing, with a little help from a multi-speed dremel tool and sanding drums. However, it worked well and I am satisfied with the results. This was then tapped at the rear to take a cap hex set screw that will act as a trigger stop. (Some ideas on the web for trigger stops include using resins to build up material on the sear. However, I like to see what is happening and control it, which is why I went this way). The set screw can then be taken out each time the bolt is removed and put back ready for shooting, after the bolt is back in the receiver.

Other parts adapted or made this session were the scope rings and two levels. This included the manufacture of both levels using basic equipment, but I wanted them silver in colour and with a blue level, matching the stock colour. Therefore I had to make them! The scope rings were just altered in colour by taking off some of the black finish with abrasive cloth. New stainless steel hex set screws were added to finish the effect. Not everyone’s taste, but I like it.

My last, completed work, for this time was adding the new Cicognani barrel tuner I purchased. This is an excellent product and I went for a European model rather than as a US made version. There are a variety of types out there and it is worth having a look around. Varide Cicognani made for mine for me especially as I wanted it in silver, to keep with the look of the rifle. At £105, with postage, it comes in at around the same price as most US made versions. Many thanks to Varide Cicognani for an excellent product and service. Also to Carlo for his services and translation. If you want to visit the Cicognani website, which contains benchrest and ISSF standard equipment, it can be found at; http://www.varidecicognani.com/ .

(A barrel tuner alters the vibrations in a barrel to match the ammunition used in the rifle, gaining better accuracy as an end result. In rimfire benchrest we are aiming to achieve a top score hit in the centre of the target, which measures 6.5mm at 50 meters, so the extreme accuracy is needed. For those interested in seeing the target, visit the association website athttp://www.benchrest22.org/ and http://www.varmintal.com/atune.htm for further information about the nature and uses of barrel tuners.) One point about getting hold of metals if you don’t have a local stockist, try Ebay, as there is loads of bits for small work. You don’t have to go for 3 meter lengths; you can order from 30cm onwards and get all grades of metal. I needed a small amount of aluminium for this rifle development and could not always get what I wanted

at local stores, which is why I mention it. The next part I am doing I needed a ½” billet to make the butt plate, which is easy enough to form using the end of the formed stock as a template. A bit of cutting, grinding and reducing with carbide paper will give you nicely formed butt plate. This I have yet to finish and produce a brushed aluminium effect. I would like to show this next time, where I also hope to show you the completed work.

Part 4

Well it is finished, finally! It has taken me about six months, on and off, to complete this project. During this time I have waited for parts and more importantly the time to do it. If anything, writing this article has moved me on a bit faster, as I would have been at it for another six months. Last time I was just finishing the butt plate, which was cut and ground by hand, matching up to the stock at each stage. Once the shape was achieved the plate was drilled and finished off with different grades of aluminium carbide paper, then 000 fine wire wool. The bolts holding the stock are 6mm

hex head bolts, with threaded inserts glued with resin into the stock. (If attempted, be careful at this stage as the butt is the end grain of the wood and can be damaged easily. The threaded columns do not need to be long, as they are not stress bearing. Also ensure the hole for them is drilled slightly oversized for the resin to bind to the wood.) The aluminium I used was obtained from a UK supplier on Ebay. It is amazing what you can get out there!

When finished I used a strong epoxy compound to seat the plate flush against the stock as I wanted no reassesses at all. Release agent was used so the plate was not fixed permanently. I am extremely happy with the results of this part of the project. The concluding parts of this project were final inletting of the stock, bedding (the part I dislike the most) and final finishing. Final inletting was slow and testing to ensure that the action and barrel fitted just right in the stock. The barrel had to be fully floated. This is only achieved through carefully reduction, using grit papers wrapped around a piece of wooden dowel that is the exact diameter of the barrel channel. If you sand using no former at all, the edges of the barrel channel, and receiver channel for that matter, will bevel and the finish will not look as good. A good website to visit that explains all of these procedures in detail is; http://riflestocks.tripod.com/

Bedding was achieved using ‘Acraglas’ from Brownells. This is readily available in this country and I had some from a previous project. I talked to Vince about this as he uses 'Hysol' on his centre fire rifles. The quality of this resin is probably better than 'Acraglas', but the one I used is probably all a rimfire needs. Most shooters on Rimfire Central use this and who am I to argue. One thing though, dam up all recesses, tape up all parts and put on release agent everywhere. You don’t want the action glued into the stock for good. For those using 'Acraglas', the Brownells website has detailed

instructions on its download page, and the products shelf life is well over 20 years; http://www.brownells.com/aspx/NS/GunTech/Instructions.aspx A good website to visit for bedding is the tripod one above and Eric Brookes website, as he has notes specifically related to bedding a CZ action. http://cz452.com/

Like everything else he does there is excellent information and products. One product related to this is the 'Delrin' bore guide he sells. I use this and it the best one I have ever used for the CZ. It is specifically made for the CZ action only and it aids cleaning and protection of the breech. It is a shame that you cannot get many of these products over here, as that

is something worth remedying in light of the CZ’s popularity in the UK. The final part for this project was the finishing of the stock, after everything had been cleared up from the bedding of the action. Mask off all bedding that has been done, as the lacquer will build up and destroy all your hard work. For this it was suggested by Vince and Bill Shehane that automotive clear lacquer be used, (or colour if you prefer). Several ways around this, using aerosol cans or if you have a compressor and air gun use this. Which ever you go for you will need quite a few layers of lacquer. I personally built up each layer,

polishing at each stage with 000 fine wire wool. The lacquer really needs to get into every pore of the wood grain and there is no skimping here. With the final layer polish with the fine wire wool again and then polish with a cloth until you have the required brilliance you want in the lacquer. Then it is down to reassembly and testing and I hope the photos give the rifle justice. There is a CZ in there somewhere. In fact the action and barrel are the same, so I have ended up with a good entry level rimfire benchrest rifle. I did need to get used to the new stock as shooting the rifle is very different than the standard stock. Saying that, this weekend I tested it and shot a 246 ex 250

with a lot more ease than usual. As normal it is the ‘nut behind the butt’ that messed things up. The cost of the project is down to you, as the original CZ stock can be customized easily and the barrel stabilizer is not essential. In effect the CZ could be customized for as little a £100 if you did it yourself. It depends what you want, as I could have gone a lot further. Overall I am very chuffed with the final results and you never know it may help those scores, so watch the website to see if I do any better?

Finally I would like to offer thanks to all those that helped with this project, obtaining parts and offering advice;

Eric Brookes, Churchley Brothers, Varide Cicognani, Bill Shehane http://www.scopeusout.com/, Vince, and Walther.