CZ 550 action screw torques

[Grouser]

I received a new to me 550 today and wanted to make sure things were snugged up. But I couldn’t find the recommended torque rates. Apparently they are closed up in Kansas so I’m asking here. Many thanks.

 

[Shootist43]

Grouser, I think this has come up before. Have you done a "Search" on AH for the answer?

 

[Grouser]

I tried the search gizmo but came up, surprisingly empty. There must be a zillion 550s about, and many gunsmiths here on our forum, but still yours is the first/only response. I snugged it to 30 inch pounds. That should suffice until CZ opens up again. Thanks, 43, for your reply.

I also noticed that one of the cross bolts is loose. Is it standard to snug them up with blue Loctite?

 

[Shootist43]

There was an article that discussed Action Screw torque in general, but it didn't mention CZ specifically. The consensus was 40 - 50 inch pounds. I believe mine are torqued to 45. Here is a link to the article I'm referring to:

BRNO 602 Action Screw Torque?

I have recently purchased a 1983 vintage BRNO 602 in .375 H&H. I disassembled it to inspect the barrel and that part of the action that is hidden for any signs of rust (none were there, thankfully). I now need some help here with the torque settings for the three screws - the two action screws...

www.africahunting.com

 

[Grouser]

Yep, I did see that one. Still, I was hoping for something 550 specific. I'm surprised it's not stated in their manual. I mean, they list adjustments for the set trigger (!) why not torque rates?

 

[bruce moulds]

since torquing action screws has become fashionable, people have forgotten the basic premis of this.
the reality is that if you have to adjust the torque to a given setting, it is a red light telling you that your bedding is wrong.
bedding should be stress free, and adjusting torque on the screws should not change the stresses.
lazy or ignorant bedders should learn this.
the only thing yo need to know with stress free bedding is that the front screw should be a little tighter than the rear one.
overtightening can compress the stock, inducing stress into the action.
this is where pillars are useful.
once it is all set up properly all you need is a scredriver and a brain.
bruce.

 

[Grouser]

Well, I'm half way there. ; )

 

[CBH Australia]

Bruce, common sense is not so common.
Is torqueing necessary maybe that’s debatable but consistency probably does not hurt.
I’ve read some stuff on composite stocks needing fairly high torque and like Bruce said pillars stop crushing action by overtightening.
I tried to search for torque settings for Tikka but cannot find a manufacturer recommendation or chart of torque requirements for different models, eg Tac, Synthetic stocked or timber. I have often read the synthetics need a little more torque. I did have a Synthetic Zastava .308 that used to work lose. But I would not have gone silly when tightening it either.

 

[CBH Australia]

Well, I'm half way there. ; )

Well we hope you have a brain I suggest you buy quality screwdrivers.
I think there are shooters that have limited brain capacity or doubtable intelligence.
I used to take agency rifles for an annual service as required.
I watched the you fellow check them over, test the trigger pull and check with a bore camera.
When he went over the torques settings of the stock, mounts etc of a centrefire and a rimfire I asked what settings they should each be. His response was they torque them to manufacturers recommendations, the rimfire mounts were off ebay and came in a blank box so good luck getting a manufacturer specification if we cannot find specs from the big companies.
I don’t shop there much and never ask their advice.

 

[bruce moulds]

chris, there are synthetics and synthetics.
some are quite soft and some harder.
hs precision, mcmillan, and brown precision are among the good ones that have min flexibility and compression.
some of the cheap factory rifle options are just moulded plastic.
bruce.

 

[bruce moulds]

Well we hope you have a brain I suggest you buy quality screwdrivers.
I think there are shooters that have limited brain capacity or doubtable intelligence.
I used to take agency rifles for an annual service as required.
I watched the you fellow check them over, test the trigger pull and check with a bore camera.
When he went over the torques settings of the stock, mounts etc of a centrefire and a rimfire I asked what settings they should each be. His response was they torque them to manufacturers recommendations, the rimfire mounts were off ebay and came in a blank box so good luck getting a manufacturer specification if we cannot find specs from the big companies.
I don’t shop there much and never ask their advice.

chris, that guy was just trying to make the blind blinder by blinding them with a science he did not understand himself.
bruce.

 

[walk-in]

First off.....congrats on the new rifle. I simply don't think you can go wrong with a CZ 550. One of my big regrets is that I didn't buy more of them back in the '90s when my local gun shop was selling them in the $400-$500 range. Unfortunately, I was young and poor at the time.

I've not noticed action screw torque to be particularly critical on most of my hunting rifles (bench rest might be a different story). I think it is more important that they be snugged down than what the precise torque is. The 1 exception I have noticed on my own rifles is the Ruger M77. This seems to be common with those. Mine shoots noticeably better not only if I properly torque the action screws, but also do them in the right order. Others I have talked to say the same. I have never had this issue with a CZ, Husqvarna, FN, Sako, Winchester, etc.

 

[CBH Australia]

chris, that guy was just trying to make the blind blinder by blinding them with a science he did not understand himself.
bruce.

Correct, he is young so I don’t know what his experience is or if he has any training or qualification. He is operating under the dealers licence that in my state is an “Armourers Licence” that allows them to trade and also charge to repair or modify.
When people try blind me with Bullshit I wonder if I look like a Dumbass or something , I know they are talking out of their ass but do they believe themselves or are they the dumbass who thinks they are expert.
As for synthetics I have said that cheap plastic stocks are cheap, expensive synthetic stocks are expensive.
My Tikka CTR stock is fit for purpose but I generally don’t like cheap synthetic stocks.
I think manufacturers like to define quality stocks as composite as they use a composite of quality materials.
I have a Bolly stock made from Carbon Fibre composite. Made in South Australia, Australia . It has a carbon fibre bedding block in lieu of pillars and I think they recommend a torque setting of about 45inch pounds and the use of a steel or alloy bottom metal. Those blokes are engineers and shooters.

 

[Grouser]

Thanks, Walk-In. The 550 is the most substantial rifle I own, by some margin. It was made in '08 and apparently shot very little. I believe even substantial .375s can be damaged by shooting with the action too loose or too tight. I figured 30-35 inch pounds would suffice until I learned better. And this was right much more than it was when I got it. Now I'm afraid to ask about loose cross bolts.......

 

[bruce moulds]

chris,
just looked up bolly.
conceptually they look very good.
pity they are not in america in a way, as the market there would support a greater choice of designs.
bruce.

 

[Wyatt Smith]

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

 

[bruce moulds]

if you use the same torque front and rear it is wrong.
front should always be tighter than rear.
bruce.

 

[CBH Australia]

I bedded my own stock for a .458wm and later transferred that stock to the .375H@was happy it was a snug fit.

If you are concerned look into bedding. Research it and see I found you are confident to do you own or willing to pay a professional. It can’t hurt anything. When the pillar bed by putting small aluminium tubes vertically for the action screws it stops the compression of the stock material. It cannot hurt and if you torque it then it should stay torqued.

As for the cross bolts, the blue loctite and nipping them up firm with a brain and a quality screwdriver could not hurt. I believe they keep lateral tension on the stock to prevent splitting, I guess they also keep the stock together by using this tension and extra strength in the stock when recoiling.

Opinions and experience will vary. As shooters we have different needs,
Example, my gunsmith is a competitive F class shooter and excellent machinist. He also culls animals but I had ideas what I wanted as a hunter and had to reiterate that it’s a hunting rifle we have different requirements and ideas.

I’m not sure bedding will see a great gain in accuracy in a .375H&H but only tried and tested Will tell. Bunnings or Walmart might do a cheap Dremel tool or equivalent, bedding epoxies are available either as a Dezcon product or a specific rifle bedding compound and you need to filter the Internet hits for the good and bad for product and method. At least follow a general consensus as opposed to the odd comment. Your gut, your requirements matter. If you form the view that something is good, what you want or what suits, read enough to support this. If you find enough contrary yet to what’s you thought then rethink it, a heap of other people might be right something might be a bad idea.

I think you are on the right track, the right forum and asking the right questions. That’s a bloody good start. Don’t be blinded by salespeople or others. I’m not an engineer or competitive shooter but otherwise pretty hands on learning all the time so I have tinkered and learned from my mistakes at my own expense.

I’m not arguing with Bruce but what I was always told is to nip down the front first, something I done with .22’s and others for a long time. I doubt 30 or 35 inch pounds Will hurt but I have never read to go higher with timber stocks either.

As far as Composite stocks. I think Bell and Carlson make a drop in fit CZ550 stock. It has a full allloy bedding block that takes the place of the aftermarket epoxy bedding you might do in a timber stock. The trade off is it might not look like a traditional safari rifle. I stayed with timber. To me Synthetics and stainless are for foul weather, Alaska and cold climates. None of which I frequent, Hell I’ve never been to Alaska.
I would hunt foul weather , cold and Alaska if I could hunt bear, that would be cool.

 

[Grouser]

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.

 

[fourfive8]

Those torque numbers seem as good as any. I don't think there is an absolute best torque for action screws and it depends on how the bedding is supporting the barreled action and the material involved. As has been posted, pillar bedding removes most of the variables for best torque for the two primary action screws. I think many factory reps from different companies simply respond to the torque question with something like "good and tight" or something similar. I know that was the Ruger response a few years ago when asked about their M77 action screw torque recommendation.

The front barrel screw on the CZ 550 or BRNO 602 is somewhat like the front barrel screw on pre-64 Winchester M70. Really no exact formula for how tight it should be. It may depend on where the barrel contact point is on the forend and the individual barrel harmonics of any one load. Many people, including some well known dedicated pre-64 M70 shooters of the past, swore by certain ways to treat that front barrel screw. Most found by experimentation, each rifle/load liked a different amount of torque applied to that screw. I don't remember any suggesting removing it. There are even some barrels/rifles that seem to like quite a bit of upward barrel pressure near the end of forend with many stocks having a raised area for barrel contact near the forend tip. I kind of think of the barrel as a tuning fork that is attached most securely near the base end. When the rifle fires and the bullet is traveling down the bore, the barrel, like a tuning fork prong, is vibrating at some frequency, in some direction. That could even include a circular component. I think and have found some evidence for the worst bedding that causes the most unpredictable accuracy is inconsistent and shows very light contact of the barrel at some point along the forend. By contrast, the best sometimes is a free floated barrel or sometimes the best is a definite barrel contact point with upward pressure somewhere along the channel near the forend tip. Imagine very lightly touching a loosely held, ringing tuning fork up against a solid object. It will start jumping randomly all over with an intemittent buzzing noise until the vibration dampens to a stop. A barrel that has inconsistent, light contact with the stock somewhere along the channel would likewise act like that tuning fork touching a solid object. How that barrel screw is tightened down, will determine how the barrel harmonics act when fired and ultimately can directly affect accuracy. I am certain the best torque for that screw is not very predictable so will require some systematic testing for each individual rifle/load.