That's crazy how big a difference that made. I still need to go back and test this myself but really great to see examples.

 

CZ says 25 maximum or the wood starts crushing. If I increase from say 15 to 17, I will back off first and then torque to 17 otherwise it seems like the bolt will stick and not tighten at all. I have found that the sweet spot on Varmints is 15 to 20 and LKA's evaluation verifies that. One thing I question is Norma Tac. You take away those two fliers and 20 is a tighter group. He shot 12 groups and he said they were consistent. Looking at 15, 17.5, and 20, I believe I would have shot 10, 5 shot groups, at each setting and see which one was the best overall. He may have done that and I am misunderstanding. I have some old Wolf Match target that I would have used for that over Norma tac. All my guns seem to love it but I am getting low. Also dont be fooled by Norma Match. I would take CCI SV over that stuff at half the price and better consistency. YMMV

 

When I checked mine they were set on 11. 22.5 was the sweet spot for mine.

 

When I got my MTR a couple years ago, I tested quite a few different torque settings. It is amazing the difference that it makes. If I remember correctly, I am at 15 in the front and closer to 20 in the back.

 

Shooting a CZ 457 Varmint MTR with Norma Tac 22 ammo.
I shot a 5 round group at each target at 50 yards.
Using a Wheeler F.A.T wrench. Starting with 15 inch/pounds with 2.5 inch/pounds increments to 30 inch/pounds, I adjusted the action screws.
It seems as though the 15 inch/pounds setting shot the best group.
Then reset the action screws back to 15 inch/pounds, I shot 12 targets with 5 rounds each and the groups remained consistent.
Next I will zero the scope in, but that's for another day.

View attachment 461284

have you bedded the action? if you havent you can close those groups up with some better ammo. and maybe with that ammo.

 

Action screw torque is my next test. I have been playing with bolt shims my measurements showed that I should need somewhere between .0015 and .002. I started running the .002 and saw a noticeable improvement especially in ammo that the gun hasn't liked much before. Switched to a .003 to see what that did and the grouping got worse. Now going to try the .0015 and see what that does. After I figure that out I am going to try the action torque and see what that does.

 

By chance did you notice less clearance/float in the channel at the higher torque values? Using paper or something like that?

 

Honestly, I didn't even think about checking that

 

I also did this with a 10/22 I own. Ruger says 30 inch pounds of torgue. At 30 inch pounds my 10\22 patterns like a shotgun, many hours at the range resulted in 18.5 inch pounds of torgue is where my gun patterns the best. My CZ Scout also shoots best at 18.5 inch pounds.

 

Suggestion to anyone with a new CZ rifle.
Always loosen and retorque the action screws. Some of mine were extremely over torqued from the factory. Including the barrel to action torque.

 

I agree, I have read on multiple sites where the grub screws (the barrel to action screws) were incorrectly torqued, some people were reporting as much as 60 pounds in one of the two and barely finger tight on the other. They should be in the 30 - 35 inch pound range, I don't remember the exact number right now.

 

My un-pillared AT-One seems to be happiest at 23 inch/lbs.

 

I tried the torque screw adjustment method several times on one of my guns. I could never settle in my mind about my results. I felt like I was chasing the torque every time I loosened and tightened the screws on a wood pro- varmint stock. At 25-50 yards, there’s 5-10 brands that look good. At 100 yards, there’s maybe 4-5 that will Usually group well and none of them are cheap. Your shortcut to accuracy is expensive ammo.

 

Pull your barrel off the receiver “so barrel weight is not an interference” and place receiver into stock with just two fingers holding it in place. Now add a little pressure to one finger than the other causing a forward and rearward pressure on the receiver.

“IF” The receiver move at all either rocking like a teeter totter front to back or tries to roll left and right in the inletting for the receiver, no amount of differential pressure , greater pressure, lesser pressure, will do a thing for your rifles and groups. If this condition exists the rifle will shoot shotgun patterns until you remove any receiver movement aka some form of bedding.

If you have played with multiple torque settings on your takedown screws and the rifle won’t settle down and there are no other issues with the rifle then bedding is a must and I would start off with any form of tape bedding weather you use aluminum tap or masking tape. You add a little tape at the forward and rear take down screw perpendicular to the action until the action fits snug with no movement in any direction then put the rifle back together and start over. Start with both front and rear at 10 inch pounds buy snugging the front first then the rear” snug each then increase each afterwards to 10 or 15 inch pound going at a few pounds at a time”.

Shoot some groups and if all is well leave it alone, if not then tighten the front 5 inch pounds and repeat until desired results are achieved tightening the front then the back at 5 pound intervals .

If this does not work at least temporarily then you have an undiscovered issue somewhere else.

James

 

Pull your barrel off the receiver “so barrel weight is not an interference” and place receiver into stock with just two fingers holding it in place. Now add a little pressure to one finger than the other causing a forward and rearward pressure on the receiver.

“IF” The receiver move at all either rocking like a teeter totter front to back or tries to roll left and right in the inletting for the receiver, no amount of differential pressure , greater pressure, lesser pressure, will do a thing for your rifles and groups. If this condition exists the rifle will shoot shotgun patterns until you remove any receiver movement aka some form of bedding.

If you have played with multiple torque settings on your takedown screws and the rifle won’t settle down and there are no other issues with the rifle then bedding is a must and I would start off with any form of tape bedding weather you use aluminum tap or masking tape. You add a little tape at the forward and rear take down screw perpendicular to the action until the action fits snug with no movement in any direction then put the rifle back together and start over. Start with both front and rear at 10 inch pounds buy snugging the front first then the rear. Shoot some groups and if all is well leave it alone, if not then tighten the front 5 inch pounds and repeat until desired results are achieved tightening the front then the back at 5 pound intervals .

If this does not work at least temporarily then you have an undiscovered issue somewhere else.

James

Had not thought about taking the barrel off, that makes sense, it would also give you much better visibility to the action. Thanks

 

Very interesting how that changed the group sizes. Thanks for sharing the results of your testing.

 

Running 25in-lbs on all of our (heavy barrels) 457`s. No pillar work or bedding, all are just the way they came from CZ, no complaints.
These CZ`s are more accurate than i am capable of anyway at my age and eye sight. My wife now out shoots me more often with her CZ`s

 

Remember,, don't loosen your screws with your torque wrench. Use a separate screwdriver and then retorque to your desired weight.

 

Mine were not very tight from the factory, about 23#. I replaced the trigger and tightened to 23# to start.

 

25 is the CZ maximum spec but I have found that 15 to 20 is preferred on all my CZ's for accuracy

 

Good info. I have on one the way

 

For what it's worth, I've tried several settings from 15 to 30 in/lbs. I found that 15 and 17 in/lbs shot best in mine. It's fully pillar bedded using JB steel reinforced epoxy.

 

I wonder how many people are convinced the have a bad barrel and give up on it, and the only problem is over torqued Action screws?
I think alot of people would over tighten the screws if they didn't use a torque wrench.. 30 inch pounds ain't much and evenat that point it seems it binds the action up.

 

I just put my 455 in a MTD Oryx. I was asked if I was going to torque it to 35 with the chassis? I said why? It ran best at 20 in the original wood varmint stock. I probably should do a test to see if that has changed or not but its shooting good so I think I will leave it. I have 3 CZ's and they are all torqued from 15 to 20 in lbs.

 

Torque Table Standard Bolt Sizes SAE

The following suggested tightening torques provide an excellent starting point for determining torque requirements. Remember, you may need to vary these numbers somewhat based on the individual joint or the amount of fastener lubrication.

www.engineersedge.com

Check out the maximum torque of #8 and 10 screws. It is no where near 25 in/lb. That's way too tight. Hence better groups at around 15 to 20. My CZ 457 went haywire recently. I rechecked torque on the action screws and it was at 22. I have a pretty accurate wrench, but now I'm questioning it. I retightened it to 19. I'm heading out this morning to test it. I'll be taking my wrench. It is in a Woox stock, un-bedded for now.....

 

Mark, the action screws are M5 which the maximum torque specs for that bolt are 4.5 ft lbs or 54 in lbs. M5 is around the equivalent of 12-32 SAE not 8 or 10. The action itself only has a few threads in them. CZ says maximum torque on those bolts is 35 in lbs. In a stock CZ wood stock, you can crush the wood going higher than that without it being pillared. That being said, I have found that my 3 CZ's like between 15 and 20. I recently loaded two of my guns into chassis. I see where many people increase their torque value in a chassis and I question that thought process and maybe someone in here thats more knowledgeable can elaborate as to why the increase. I understand we are talking about a metal chassis but if your gun is shooting good at 20 in lbs in the wood stock, why not torque it to 20 in the metal chassis? I am waiting for a new chassis from PDC and when I get it I will probably take all 3 of mine to the range and test fire them at different torques to see if there is any change. For now, I am happy with the way they are all shooting and dont really care about testing them. Am I wrong in assuming that a Woox chassis is metal inside? I thought they were and bedding wasnt necessary.

 

Im running my LRP at 31 Inch Lbs and she loves it, but havnt tested any other settings as yet. CZ youtube tutorial says 31 in lb so thats what I went with. Pretty new to all this.

 

Wow didn't even know this was a thing I'll have to test it out next range trip and see what effect it has

 

Mine shoots great at 20 in/lb.

 

My MTR is in a PDC chassis, set my action screws at 20lbs since the aluminum chassis won’t flex or compress like the factory stock

 

I did the same thing with mine. It was happy in the wood stock at 20 so why change it. I was going to do a torque test on it but the darn thing shoots so well.....if it aint broke dont fix it!!

 

Edited to remove double post due to technological issue.

 

Newbie here. Can somebody provide a basic explanation for how the action screw torque (and tension) affect the shooting accuracy?