CZ 550 action screw torques

[CBH Australia]

CBH, thank you for your responses.
I have torqued all three to 30 and then re-torqued the center screw to 35. There is bedding material about the recoil lug and also where the barrel rests against the ‘stay’. My research on this forum indicates that many prefer to toss the barrel screw in the trash, but I figure CZ has a reason for this addition so I’m leaving well enough alone. I am holding a rifle that looks to have been sitting for the last ten years. Just tidying up and snugging up here and there. Enough but not too much. Hopefully in the next week I’ll have a chance to get to the range. Wish us luck and thanks to all again.

Yes, best of luck. I like the .375 H&H, I bought one as I considered it a Classic. It seems to be versatile too.

Agreed on CZ having a reason for the centres screw. When I pulled down my first Tikka T3 to check it out I found the recoil lug in the stock and it locks into a recess under the action. I thought it was backward and unlike anything I had seen. I later drew the conclusion that Tikka engineers are smarter than me and while it might be a budget or cost saving solution it does work.

 

[425SCHADE]

Can't remember where I found this one but it's a good one to start with. Accuracy testing will confirm what your rifle likes.

 

[bruce moulds]

if forend pressure on the barrel makes a rifle shoot better, here is another red flag as to incorrect action bedding.
it was a zig that factories brought in to counteract a zag.
ruger even used to deliberately bend their m77 actions as well, an even worse no no.
even if it improves grouping, in wood stocks it will vary, and it will also guarantee zero shifts in general, and make the rifle shoot away from whatever the forend is rested on.
properly bedded action and free floated barrel are a basic, except on a bug caliber stock wrecker where a barrel mounted recoil lug is a necessity.
but such a rifle does not have to be as accurate generally.
as chris says, tighten the front action screw first, then the rear one a little less second.
if there is a middle action screw, just snug it up very lightly.
good bedding requires that the action will be floating where that screw is.
with regards chassis stocks, they will usually shoot better when properly bedded.
a good bedding job will actually allow the barreled action to fall out of the stock if you turn it upside down with no screws.
if too tight, the action is not free to return to battery in the bedding consistently after each shot.
this is also why the rear screw should be less tight than the front action screw.
bruce.

 

[shootist~]

PM sent.

I tighten mine to 35 in pounds. No real reason why, other than it feels about right.

Same here and for the same reason. This is a Bell & Carlson stock, btw and it's a 9.3x62.

 

[CBH Australia]

Can't remember where I found this one but it's a good one to start with. Accuracy testing will confirm what your rifle likes.
View attachment 381889

Mmm, maybe on. NZ website , forums. I think I’ve seen the exact same or similar.

It’s interesting that not all manufacturers don’t readily list a recommendation.

And what is a .425 Schade? Can you post cartridge pics please?

 

[Grouser]

fourfive8, the barrel screw does have me baffled. I'm coming from Weatherby. They have been manufacturing quality rifles for a while. On their website, they publish torque rates for their wooden stocks as well as the B&C they use. Wooden: 35 inch pounds. Tighten the rear screw and then the front screw. B&C: 55 pounds. Tighten the rear screw first. My wooden stock, with forearm pressure, shoots sub MOA consistently. The B&C stocked, free floated, has shot sub 1 inch groups at 300 yards. Neither has a barrel screw. So, the CZ has a barrel screw. And it is bedded against something they named a stay. BUT the screw does not screw into the barrel. It screws into a nut like thing that is able to slide in a channel slotted in the bottom of the barrel. I believe this is designed for flex as the barrel heats or the wood may expand. Hmmmm....... Now thinking about it, this screw had what looked like gunk OR a locking compound on it when removed. Upon reflection, I think I will take this screw back out, apply a little blue juice and just snug it up so it can flex. As I said, the CZ is a different animal to me. Thanks again.

Trent

 

[IvW]

What caliber is it?
I never had issues with mine I own 4 Zkk ones tight is tight never torqued any...from 243 to 500 Jeff....2 more on the way 7x57 and 300 WM.
Use the right screw driver though...

 

[Grouser]

IvW, I don't believe I am having issues. It's a .375 H&H : )
And I'm using Wheeler's FAT wrenches so fit is good, thank you.
I'm just dressing down a new to me firearm and it being my first CZ, trying to get into their mindset. Thanks

 

[IvW]

NP I never had issues. Sometimes you strip rifle in the field and re assemble. Tight is tight and that is that for me. These are not benchrest rifles.
Especially in larger bores. Very reliable and bullet proof working rifles get the job done every time....

 

[425SCHADE]

Mmm, maybe on. NZ website , forums. I think I’ve seen the exact same or similar.

It’s interesting that not all manufacturers don’t readily list a recommendation.

And what is a .425 Schade? Can you post cartridge pics please?

Pic from RCC below. Haven't got my hands on the cases as yet, hopefully they're not far away.
In short, a necked up and slightly improved .416 Rem. Nothing too outrageous.

 

[CBH Australia]

Pic from RCC below. Haven't got my hands on the cases as yet, hopefully they're not far away.
In short, a necked up and slightly improved .416 Rem. Nothing too outrageous.


View attachment 382093

Thanks, it's one I had never heard of.

 

[gbflyer]

Pic from RCC below. Haven't got my hands on the cases as yet, hopefully they're not far away.
In short, a necked up and slightly improved .416 Rem. Nothing too outrageous.


View attachment 382093

Something about that just oozes seriousness. Very nice.

 

[fourfive8]

fourfive8, the barrel screw does have me baffled. I'm coming from Weatherby. They have been manufacturing quality rifles for a while. On their website, they publish torque rates for their wooden stocks as well as the B&C they use. Wooden: 35 inch pounds. Tighten the rear screw and then the front screw. B&C: 55 pounds. Tighten the rear screw first. My wooden stock, with forearm pressure, shoots sub MOA consistently. The B&C stocked, free floated, has shot sub 1 inch groups at 300 yards. Neither has a barrel screw. So, the CZ has a barrel screw. And it is bedded against something they named a stay. BUT the screw does not screw into the barrel. It screws into a nut like thing that is able to slide in a channel slotted in the bottom of the barrel. I believe this is designed for flex as the barrel heats or the wood may expand. Hmmmm....... Now thinking about it, this screw had what looked like gunk OR a locking compound on it when removed. Upon reflection, I think I will take this screw back out, apply a little blue juice and just snug it up so it can flex. As I said, the CZ is a different animal to me. Thanks again.

Trent

Yep, it is baffling how to treat them for best accuracy/consistency. I've had several pre-64 70s. IIRC for best accuracy and consistency within their individual capability, I just snugged the barrel screw down fairly tight. At least enough that, in my experience, it wouldn't have a tendency to loosen or back out. Not quite as much torque as the main action screws, but pretty tight. I had a Win 52 heavy target 22 that had two opposing set screws located under the barrel in the forend that could be tweaked to add varying amounts of upward pressure, or at least pressure counter to the basic gravity affecting the heavy barrel. Each sitting at an opposing support angle form one another. You could actually adjust each screw to a precise contact-to-barrel position by using an ohmmeter. You then had a base line of zero for each screw from which to further adjust each for pressure. Guaranteed, those are most interesting rifles to tune!!! They requre a lot experimental work to adjust for best accuracy. My Win 52 Sporter has a single barrel screw in the forend and I just snug it down really well so it won't loosen and in that configuration it is inherently a very accurate 22rf without any further need for tweaking. I experimented some with that screw removed but noticed no affect on accuracy.

I am unsure of the validity of the sliding nut design used for the CZ barrel screw. Still scratching my head about it. My BRNO 602 in 375 HH has that attachment design and I just snug it down tight. Additionally, I think the barrel lug contacts the metal shim and recoil block in the stock when all is tightened down. The barrel also rests on the bottom of the barrel channel near the forend tip producing a small amount of upward barrel pressure there with all three screws tightened down. I agree with @IvW in that if these are shooting with reasonable accuracy adequate for the intended purpose of serving as tough use hunting rifles, worrying about minute increments of accuracy may not matter much. Consistent, reliable function with reasonable accuracy are the important considerations. So far mine shoots consistently well with the front barrel screw tightened down pretty tight with the main actions screws torqued slightly tighter yet. I don't notice any significant change of POI over time with that set up. I've shot it checking for POI and accuracy at temps ranging from maybe 90'F down to about 15'F with little significant change.

 

[425SCHADE]

Thanks, it's one I had never heard of.

No you wouldn't have yet, need to get the rifle build completed and some loads made up.
Will post some more pics as it progresses.

 

[425SCHADE]

Something about that just oozes seriousness. Very nice.

Yep... aiming for the proven standard of 400gn/2400fps.

 

[CBH Australia]

Something about that just oozes seriousness. Very nice.

What naming your Wildcat after your online handle?
Or building something shit hot?
Sounds like a winner with those specs.

 

[Grouser]

fourfive8, there is bedding compound between the nut (119, able to slide in the channel) and the stay (107). So I assume they have a close relationship. I would be fine with 2 moa. I'm not hunting chipmunks with this rifle. Now if the weather will clear.......

 

[SRvet]

Does the 602 use the same stay (107 on the above picture) as the 550? I bought a 602 but there was no stay present when I took the stock off. There is a slot in the stock and I have wondered about trying a Tikka style recoil lug in this slot rather than having no lug present

 

[Grouser]

Sorry, SRvet, I haven't a clue. I'm new to CZ. Worth a call to them.

 

[Hunter4752001]

SRvet. The 602 is similar to the 550 except that whereas CZ550 part 107 is like a sideways F, the corresponding part on the Brno 602 is like a sideways L (see part 79 on the attached pdf).