Gunsmithing Torque value's on action screws?

[JLM]

As a general principal how much torque do you guys generally run on your action screws?

Is 40in/lbs sufficient for a .308 WIN?

I'm running my shit unbedded with no pillars for the time being, it seems to be shooting great. McM A1-3 with the 'standard fill'.

Thoughts appreciated.....

 

[Tinytim]

Re: Torque value's on action screws?

65in/lb

 

[sobrbiker883]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tinytim</div><div class="ubbcode-body">65in/lb </div></div>

I would guess you missed reading the OP's post. He said no pillars.

35-40 in/lbs should be fine. Put some pillars in and properly bed the stock if you want optimum results.

 

[Hateca]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tinytim</div><div class="ubbcode-body">65in/lb </div></div>

I would guess you missed reading the OP's post. He said no pillars.

35-40 in/lbs should be fine. Put some pillars in and properly bed the stock if you want optimum results. </div></div>

+1 any more then that you will crush the crap out of that stock.

BTW 65 inch pounds is not the be all do all torque value for bottom metal.

 

[gunsandcigars88]

Re: Torque value's on action screws?

Ok, I quickly admit that I am new to this type of stuff. Dabbled in guns and working on them my whole life, but new to precision rifle type stuff. On my Remington 700 SPS Tactical(Hogue Overmold Stock dual aluminum pillars) I have mine torqued according to what the book says. Rear screw to 5 inch lb.s, and the front screw to 15 inch lb.s? What will I gain from torqueing those down to 65 inch lb? I have heard from several to torque it down to 65 but don't understand why. I hear accuracy will increase, but I am currently getting under .75 MOA accuracy as is. Should I torque them down to 65?

 

[427Cobra]

Re: Torque value's on action screws?

Stock bottom torque to 50 inch pounds. 5 inch pounds is nothing, the action is moving during recoil, set the rifle on its but, torque the front screw, then the rear, and try it out GSC88.

 

[chpprguy]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">
BTW 65 inch pounds is not the be all do all torque value for bottom metal. </div></div>

Can I ask you to "expand" on this?

 

[1SMALLJOHNSON]

Re: Torque value's on action screws?

MAKE ABSOLUTELY SURE YOU'RE IN INCH-POUNDS RATHER THAN FOOT POUNDS!!!

 

[sobrbiker883]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: chpprguy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">
BTW 65 inch pounds is not the be all do all torque value for bottom metal. </div></div>

Can I ask you to "expand" on this?

</div></div>

I'm not attemting to speak for Randy, but I know you can do damage to factory bottom metal by going 65 in/lbs even with a pillared stock-the factory (non-steel) bottom metal should be good up to around 50 in/lbs.

 

[Hateca]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: chpprguy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">
BTW 65 inch pounds is not the do all be all torque value for bottom metal. </div></div>

Can I ask you to "expand" on this?

</div></div>

Sure, where is it said that 65 inch pound is the norm? It's not. Do you know what Remington recommends for factory spec rifles? Do you know what AICS recommends?

Some rifles will shoot very well with 65 inch pounds and some won't. Some rifles won't like the same value on both screws. Some rifles like heavy torque on the front and somewhat lighter torque on the rear, or maybe the other way around.

Point is no two rifles are the same. Some like heavy torque some like light torque. Rifles that are properly bedded can take heavier torque values and they can also take very light torque values and still shoot lights out.

Factory bottom metal by its design is in danger of splitting from high torque values.

There are too many variables to say 65 inch pounds is the do all be all value for every rifle.

Next time your out at the range take a torque wrench and switch out the torque values and see what happens.

65 inch pound is easy to visually guess without a torque wrench. Hand tight to 12 o'clock and tighten to 3 o'clock and you will have pretty close to 65 inch pounds.

 

[sobrbiker883]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">


65 inch pound is easy to visually guess without a torque wrench. Hand tight to 12 o'clock and tighten to 3 o'clock and you will have pretty close to 65 inch pounds.


</div></div>

Randy, that's one of the many great tips I've picked up from you. Its been probably a year since I've used a torque wrench on my stuff that goes 65in/lbs anymore and it has proven repeatable within 1/2moa on both optics mounting and pulling and replacing actions in stocks....

 

[skeetlee]

Re: Torque value's on action screws?

I have heard of folks actually bending the rear tang area of a rem 700 action by over tourquing the rear screw. I usually set mine aroun 35" pounds and the fron screw around 50. Thats what works for me. Lee

 

[Greg Langelius *]

Re: Torque value's on action screws?

I approach the torque question from the mechanic's point of view.

I was trained in the physics and techniques of small machine maintenance by IBM's Office Products Division back in the 1960's, which was the heyday of the electromechanical typewriter.

Not all screws and bolts are created equal, nor are the points into which they anchor. The intent of fastener torque specs is to attain a binding force which attaches components adequately to their task, without exceeding the fasteners' stress limits.

That point about 'adequate to their task' is the kicker.

A component which is simply lying in contact with another component, free to move until the fastener is secured, is a far cry from another which is nested snug within a complementary contoured recess.

In the first instance, there may not be a fastener in existence which has sufficient stress capacity to secure the components immovably. In the second instance, adequate security can be attained without ever approaching the fasteners' stress limits.

Original firearm action fasteners are properly graded to withstand reasonable fastening stresses. Keep this in mind when you consider replacing them. Keep also in mind that upgrading fasteners makes sense, but the fasteners' attachment points remain unchanged, and can be stressed by higher grade fasteners to the point where they can fail.

When combining components, I make absolutely certain that when failure is likely, it is the replaceable part that does the failing. A good example of this is the grip screw socket nuts on the 1911's grip frame. When something strips, it's not the frame.

I don't concern myself quite so much with torque as I concentrate on friction.

I make a serious effort to ensure that the male and female threads are clean and dry, no lube present. I cautiously tighten the fastener until I feel it grab, where the friction reaches the point where the fastener actually flexes initially. Increasing torque slowly brings flex to the point where it overcomes friction, and we feel the fastener jump to a new rotational position.

That's where I stop.

I don't know what this value will be, but I'm reasonably certain I've established a reasonable degree of friction while staying within the fasteners' stress limits. I count on the friction being sufficient to prevent the fastener from backing out under operating forces. While it is not inconceivable that this approach could over-torque a fastener, I have not yet experienced any issues that would confirm that risk.

This friction relationship is too complex and delicate to be combined with lubricants or any other substance that alters that dry friction relationship. I also resist temptations to relax or adjust this relationship, as placing the parts into motion while under this degree of tension can polish the mating surfaces and alter the proper friction point.

I don't use the fasteners as a tuning adjustment, I depend on the bedding relationship to establish this tuned condition. I employ the fasteners to secure the components, and only undo the fasteners when the components must be separated for maintenance, etc., purposes.

Greg

 

[deadly0311]

Re: Torque value's on action screws?

Greg you never cease to amaze me at the amount of well worded wisdom and knowledge that you have. Id honestly love to sit down one day and have a conversation with you

 

[Clark]

Re: Torque value's on action screws?

link to Calhoon's web page about bedding with shpiel about action screw torque

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
...
Torque actions screws (1/4") to 40 inch/pounds.That is about all a normal human can twist, using two hands on a good screw driver.

Barry is only good for 25 in / lbs., but Fred does an easy 60 foot / lbs. !
...

3) Aluminum does expand twice as much as steel per degree Fahrenheit temperature change. Steel changes 6 millionths of an inch (.000006") and aluminum 12 millionths of an inch (.000012") per degree F change. But I haven't seen actual proof that the extra expansion makes a noticeable difference. </div></div>

Calhoon, an engineer, does bullet making in his own shop with his own tooling, and is much more productive than me.

I may be an engineer, but I have always worked at aerospace or medical companies with lots of employees. The jet fighter that protects you has got my designs, and are screwed together with human hands, not toque wrenches. When ever a torque wrench would solve a problem, it is by passed, as it would introduce prohibitive costs to control the process. The higher volume defibrillators are screwed together by machines, and they are torque controlled. You may need a defib if you snap off a bolt in your rifle

 

[mj2evans]

Re: Torque value's on action screws?

I called McMillan after seeing people use 65 inch/punds. McMillan says 45 should be fine (I am using just a little over that). My Choate ultimate varmint (no laughs pleaes) likes 51 inch/pounds (tried 60 and the groups sucked).

 

[ShootToWin]

Re: Torque value's on action screws?

JLM,

If its shooting great leave it be!

 

[bignada]

Re: Torque value's on action screws?

Saw Speedy Gonzalez' comment about using 45 rear and 40 ip on front action screws. Might be worth seeing if your rifle notices a difference.

 

[damoncali]

Re: Torque value's on action screws?

Hello all, I'm new here and saw this old post. I recently wrote an article about action screw torque and the engineering behind it. I'd love to hear your opinions about it. You can find it at Rifle Action Screws: Torque, Accuracy and Bedding Issues.

Thanks, and I'm glad I found this site!

 

[kortik]

Re: Torque value's on action screws?

That was a good article. Logical. I personally came to the conclusion, some time ago, that stock as a component of the firearm is actually causing quite a bit of issues by just being there. Seems logical to get rid of the convensional stock design and forget about complications. Something along the lines of PTRD-41, anti-tank rifle of WWI, with a bit more stiff receiver to insure solid scope setup, may work real well, I think... Of course, it's a bit of a radical idea, but theoretically speaking, 100% free of any bedding issues.

The only thing about using the angle as opposed to torque - this is, in theory, "potentially" precise method, but a lot more "scientific" in nature than most people can handle with confidence. Torque wrench, assuming that friction in the threads is relatively consistent, is much easier to use and is likely will provide the same result.

In general, very, very good article.

 

[Clark]

Re: Torque value's on action screws?

Katnip gets up and starts to chase [Herman], but he trips and slams into a bookshelf. A book called Sure Cures for a Spraint Arm. Katnip opens it and starts to read.

Katnip (reading book): "If your arm has a real nasty sprain,
eat a crow, and good bye pain!"

Katnip: Eat a crow.... Hmm, that sounds logical!

 

[damoncali]

Re: Torque value's on action screws?

kortik - I agree on the angle vs torque wrench. One is certainly easier than the other ( I dont' even use a torque wrench, for what it's worth - just a regular wrench). Just wanted folks to think about it and ask themselves if that torque setting is *really* as critical as they think.

I also agree on the overall design of rifle stocks being a weakness when it comes to high end accuracy - there must be a better way.

 

[kortik]

Re: Torque value's on action screws?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: damoncali</div><div class="ubbcode-body"> kortik - I agree on the angle vs torque wrench. One is certainly easier than the other ( I dont' even use a torque wrench, for what it's worth - just a regular wrench). Just wanted folks to think about it and ask themselves if that torque setting is *really* as critical as they think.
</div></div>

Use of torque wrench is very important, as most people certainly do not possess capabilities of, lets say, load cell, and can esily tighten fasteners too much, or, in more rare cases, too little.

Then you get situation when expensive stuff gets whacked, etc. Also, torque wrench does work for providing the relative consistency of deflections in rifle scope/mount/action assembly, you know well why it is beneficial.

I think the important part is to remember that torque by itself is a secondary measure of clamping forces generated by the fasteners, and also, clamping force and applied torque relationship is greatly dependent upon friction in the threads. I think as long as people keep this friction conditions relatively unchanged (say, keep threads clean and dry, with no lube present), use of torque to control deflections in assembly is perfectly acceptable and practically suitable.

For precision and long range shooters, specifically for the ones who change scope setups in a field or need to assemble/disassemble rifles relatively often, having some measure of control over deflections introduced by clamping forces of the rifle fasteners is especially critical. Nobody realistically wants or even can afford to have time to re-zero in the field. Certainly, trying to follow specific torque recommendation of, say, 62 inch-lbs., and rejecting the use of 56 inch-lbs, or 68 inch-lbs. just because it's 10% off is not as critical as applying one of these settings consistently.

I bet everybody on SH knows what I just posted, but being in torque tools business, I got to reply...

 

[x ring accuracy]

Re: Torque value's on action screws?

Every rifle is unique. There are no pat answers. Same goes with ammo. I can use the same reamer and make 2 rifles and they sometimes like ammo a smudge different than the other. This is where gray hair comes from in the shooting world, trial and error.

 

[former naval person]

Re: Torque value's on action screws?

I believe I read a reply on here a few weeks ago in which the author addressed the yield strength of the fastener as related to torque values...his conclusion was that 45 inch pounds was optimum for the 1/4 inch screws most of us use...65 inch pounds could stretch and permanently deform the screws...i.e., exceeding the elastic limit of the screw. Depends upon the grade of the screw,of course, but as Greg points out, the screw should fail before the action threads rip out. In other words, don't use a grade 8 fastener and torque it to the limit. JMHO

 

[geisterfahren]

Re: Torque value's on action screws?

65in/lb

I have a Remington model 700 xcr tactical rifle caliber 0.223 with R3 pad with an B&C olive green tactical stock (from Remington Custom Shop), 20 inch barrel. I sent an email to B&C and they replied “

We recommend 45-50 inch lbs. You can start with the rear screw with a qtr turn, go the front screw, do a qtr turn. You will need to repeat this process until you have the desired torque.”