Author Topic: Tuning CZ 452 Varminter (Read 2941 times)

Leftoverdj · « **on:** July 11, 2003, 03:37:29 PM »

I've done about what Vmaxx has done. I did a trigger job and molyed the engagement surfaces while I was at it. I got the barrel centered in the channel and played with screw tension. I tried a couple of pressure pads, but not as far foward as VMaxx put his. (I cut my pressure pads out of an old blanket from an offset press. The material is quite similar to what Vmax is using.) I've tried every kind of .22 ammo available in my area. Best is Ely Club and close if not matching is Federal Match. One batch of CCI Standard was right in there with the high dollar stuff, but the next wasn't.

I need a better scope, and I expect that I will lock the barrel stud for the front screw into place. I'm already getting better results than I ever expected, consistent five shot 50 yard groups of half inch or better, but I want MORE!!!!!!!!!!

vmaxx · « **Reply #1 on:** July 11, 2003, 05:01:47 PM »

Sorry I goofed and didn't start a new thread on the cz varmint in the proper place. I hate to recant the whole thing here but it goes something like this: put brookie's trigger kit in, sanded down barrel channel on the right side so the barrel is not touching the wood there, put a pressure pad made of old belting material about .065-.070 inches thick and about one centimeter square, glued to the forearm of the stock about one and one half inches from front of the forearm. Tighten down both screws equally and quite tight. Keep your barrel centered so it doesn't touch the wood on either side as you reassemble it.

Leftoverdj · « **Reply #2 on:** July 11, 2003, 05:25:41 PM »

What is a reasonable goal for a properly tuned rifle?

Are my occasional one hole 50 yard groups flukes or are they repeatable?

eroyd · « **Reply #3 on:** July 11, 2003, 07:45:24 PM »

So what about my 452 lux ? The stock and barrel seem to be intentionally built snug. Would there be any improvement to clearing that barrel channel or would that be detrimental?

vmaxx · « **Reply #4 on:** July 12, 2003, 05:34:49 AM »

You can actually make it worse. If its shooting good and snug down the barrel channed I'd leave it alone. A free floating barrel is not always the most accurate. If it were we wouldn't be putting pads under the barrel to try and tighten our groups up. If you can't get one half inch groups at 50yds with premium grade ammo then I would consider making some changes. I have help improve the accuracy of some rifles just by placing a thin shim about 3/8 inch wide near the end of the barrel and one near the action under the barrel portion cut out of aluminum flashing material like they put around chimneys. Its about .012 inches thick, can be cut with sissors and there is no need for wood removal. Try That first if your not getting the groups you feel you should be getting. This leaves your barrel contacting ony in two areas and its kind of a semi free float to the barrel. Cut them longer than you need them and when you tighten up the action screws you can work them back and forth til they break and you'll have them break off perfectly between the barrel and the wood and its hardly noticable. Thats one of my tips and tricks. Its fast and its cheap and they are easily removed if it doesn't help things.
good shooting to ya

eroyd · « **Reply #5 on:** July 12, 2003, 06:12:14 AM »

Thanks, sounds simple enough, I'll give it a try.

There's a good informative article in 1992 Gun Digest, "Getting the BEST from the 22 RIMFIRE", by C.E. Harris that's worth digging up.

vmaxx · « **Reply #6 on:** July 14, 2003, 12:31:20 AM »

I had some great one hole 50 yd groups but couldn't get them to repeat. Thats why I decided to add a pressure pad beneath the barrel. The gun seems more consistant now but still somewhat sensitive in the way that it is held. Not as much as before but still a factor when it comes to hitting those bullseyes on the usbr targets. I added the pad because I kept hearing others with the cz varmint models were doing so and getting increases in accuracy. I wanted to keep it free floating but it just wouldn't stay consistant. Just a good group every now and then. I haven't been able to do a 50 yd test because our range is under construction but it sure seem to do well on the usbr targets at 25 yds. I got my trigger set a 2 lbs. I probably could do better with a lighter trigger but I may want to use the gun in the field and I don't want it to be unsafe. I've taken the gun apart serveral times and don't want to take it down again unless I have to. My center fire guns have their triggers set at 2 lbs and I feel if I ligthen the trigger any more it will spoil me with the other rifles and they shoot about 1/2 moa or better.

Leftoverdj · « **Reply #7 on:** July 15, 2003, 04:36:02 PM »

The barrel lug for my front screw is loose, so loose that it will fall off when the action is out of the stock. It also bears on the bottom of the stock hole for it.

Is this normal for the CZ Varminter?

I'm just about to lock the lug permanently and solidly in place, but I thought I would check with others first.

Questor · « **Reply #8 on:** July 16, 2003, 02:03:27 AM »

Just for the record, I've got three CZ rifles, two rimfire and one centerfire, and none required any tuning to yield sub-MOA groups at 100 yards.

vmaxx · « **Reply #9 on:** July 16, 2003, 04:20:44 AM »

Left, some are using JB weld to lock the lug in place. I just slid the lug out peened down the metal just a tad on each side of the dovetail, tapped it back in with a brass punch and now it fits snug, did my best to center it in the process. Hope this helps.

vmaxx · « **Reply #10 on:** July 16, 2003, 04:36:51 AM »

Questor, Sounds like you got three nice rifles. We are actually trying for .250 or better at 50 yd with our rimfires, or as close as we can come to match accruacy and that usally takes a bit of tweaking. The bulls on the usbr targets are about the size of a pin head. Getting under and inch is good though for hunting purposes, but you'll need to do a little better for target shooting.

gunsmither · « **Reply #11 on:** July 16, 2003, 06:47:14 PM »

The easiest way I have found to lock the CZ 452 Barrel, or Receiver Lug (depending on model) in place is with a short Allen Head Set Screw of 6mm dia. x 1mm pitch x 6mm long. You can find them at a good hardware store.

Put the set screw in first to lock the lug where it's centered with a drop of locktight. Just snug it lightly; no need to dimple the barrel or receiver, just "Snug it". The action screw should be still short enough to clear the set screw; if not, shorten action screw to clear retaining set screw.

This will keep the lug in place, and you'll return the action/barrel to the same spot each time. Safe Shooting ! - "gunsmither"

Leftoverdj · « **Reply #12 on:** July 17, 2003, 02:05:50 AM »

Too late, Gunsmither, but thanks.

I actually thought of that, but then I thought of the difficulties of determining what was the right metric set screw and then finding the screw and I went the JB Weld route. I do appreciate you doing what I was too lazy to do.

But that screw would be a mighty fine thing for Brooks (?) to add to his trigger kit. And if you have any more neat ideas for the CZ, you might consider marketing a kit of your own.

vmaxx · « **Reply #13 on:** July 17, 2003, 04:03:35 AM »

This screw idea seems to be the best idea yet but like you stated leftover I had no idea of the thread pitch or length needed. Thats good thinking gunsmither do you have any ideas about pressure pads or anything else to help in accurising the varmint or any other cz.

vmaxx · « **Reply #14 on:** July 22, 2003, 03:00:36 PM »

I have just order an adjustable sear from brownells. for my varmint. Did this because I want to lighten the trigger pull to as low as i can get it and the rifle still be safe.

Leftoverdj · « **Reply #15 on:** July 22, 2003, 05:11:30 PM »

Vmaxx, could you give me the page number for that sear? Or the exact name? I did my trigger job the old fashioned way. Got it about perfect for weight, but there is just a trace of creep left. More of a slightly mushy feeling than actual creep, but I am reluctant to stone off any more of the engagement.

I broke down and bought a brick of Federal Ultra Match today. It shoots as well as anything I've tried in my rifle. Now I can tune the rifle for that particular ammo. I figger three five shot groups will tell me when something is not working. Takes a bit more shooting that to tell for sure that something is working.

This project has really gotten me going again. I don't have easy access to a range. I have a safe 50 yard range at my home, but have neighbors near enough so noise is a consideration. I doubt they can even hear standard velocity .22 though 150 yards of woods. No complaints yet and I've shot a pile of ammo in the last few weeks.

vmaxx · « **Reply #16 on:** July 23, 2003, 03:16:26 PM »

For the sear go to: Brownells.com and in the search collum type in the word sear and the sear for the 452 cz should be the last item at the bottom of the page. If you still can't find it I get you their phone #

vmaxx · « **Reply #17 on:** July 25, 2003, 01:31:32 PM »

This was a very difficult job because of the spring and ball bearing that the sear pivots on. I lost the ball bearing that came with the gun. Luckily Brownells is aware of the situation and they send you an extra ball bearing. I finally got the sear in with the help of my lovely wife. I needed a third hand and she was there. Oh yes and remove your brass shim if you happen to have installed one. I put the lightest spring on it that was in the brookie kit when it came down to putting things back together. The spring wouldn't work as it could not push the tigger enough to return it. Tired of driving pins in and out by this time I just put back in the spring I had in it before. I knew at least it work. Trigger pull is still around 2# or a little less with no creep. Luckily the adjustment screw didn't seem to need to be adjusted. That was good because I couldn't get the wrench down into the alan head screw to turn it. I am almost back to where I was but I don't plan on driving out any more of the pins to make adjustments. They are not easy to work with and this type of work is not for the novice. The sear is stainless steel by the way but I tell you $70 is to say the least a major investment, but I feel it is worth it, if you are sure you plan to keep your CZ rifle for a long time.

vmaxx · « **Reply #18 on:** August 10, 2003, 12:58:27 AM »

I put the sear in and went to a lighter spring. My trigger pull now is at 1-1/4 lbs and that is as light as I can go and still be safe. I ended up JB welding my front barrel lug in the name of accuracy. It was allowing the barrel to move around as I shot. The lug bottoms out and in the stock so the screw is only tightening the lug and not putting any tention the barrel. leaving just the one action screw to do all the work and its not quite heavy enough to do all the holding. I also removed the pressure pad because the rifle never had a chance at being accurate til I bonded the barrel lug.
Took it the range for and accuracy test and the rifle shot groups under .400 inch at 50 yds with CCI standard velociety ammo. That being the case I see no reason to put the pressure pad back under the barrel at this time. I did bed the area around the lug so it can't shift around. The barrel is basically free floating as it is now. I've considered glass bedding the action but some of those that have done it saw no change in accuracy. I feel I'm on the trail of accuracy, just need to try some different types of ammo to see what works best.

Leftoverdj · « **Reply #19 on:** August 12, 2003, 03:47:08 PM »

I'm in mourning for Federal Ultra Match ammo. Found out that was what my gun likes best and they killed it on me. Got two bricks and I am hoping that some Wolf will come on the market before that is gone.

vmaxx · « **Reply #20 on:** August 12, 2003, 04:13:14 PM »

Stay away from the match extra wolf. I had bad luck with it.

Leftoverdj · « **Reply #21 on:** September 03, 2003, 12:23:50 PM »

Here's how mine is shooting now.

vmaxx · « **Reply #22 on:** September 03, 2003, 08:13:12 PM »

looks good leftover. My groups are simular. since I jb welded my barrel lug and put some bedding compound to the stock in the area of the barrel lug. I also went back to free floating the barrel and removed the pressure pad. My last time out I had fifty yd groups of .436, .281, .356, for five shot groups and I had a three shot group that measured .256 inch. once the wind got up my groups went to numbers in the .600's or so with one group spreading out to .927 inch. This was with cci mini mag hp.
I been experimenting with the Paco kelly ACU'RZR with mixed results. The .356 inch group was with the acurized ammo. But I have also seen it cause groups to open up as much as 50%. Can't say for sure yet if it is worth the cost and the trouble of sizing the cartridges. I'll let you know after more testing. Don't run out and buy one just yet.
Been a while since you posted, good to hear from you and see that you are doing well with the targets. Keep up the good shooting.
Dave