Questions for those who build guns

[jaym_100]

A friend of mine took his rifle to a custom gun shop around here. I didn't even know they existed. The rifle he has is custom rem 700 on an hs precision stock. I had the rifle for several years and it shoots great most of the time (which probably meant it was shooting bad because of me). I have always torqued the action at 65 pounds like hs precision states. So the guy at the gun shop takes it apart to check it out and says to torque it to 35lbs. He says you will get better accuracy at 35lbs and he stated that he has been building rifles for years. I have learned over the years that there are plenty of idiots around that should know what they are talking about but don't. That being said this guy might know his shit. It is epoxy bedded if that makes a difference. Is he right?

 

[strike33]

the 65 pounds was decided way back when the M24 was being tested. They settled on 65 as that what was available for a preset torque wrench. The actual best figure was an odd number. I would have to research but it was something like 57-63.
To find the best for YOUR rifle it takes some experimenting. Try 45 and work your way up in increments.
35 does seem on the lighter side. normally it falls around the 50-65 range. And some have different settings front to rear.

 

[MoBoost]

There are many variables to answer the torque setting question with one number - some stocks will take the higher torque with no deformation better than others. With that said, I have tested the torque setting on various rifles - and my personal experience is that there is no necessity to go over 30in/lb, and most my vintage rifles are at 20-25in/lb.

It really doesn't make sense to spend time and money for stress free bedding on a quality stock and blueprinted action - and then throw it all out of the window with stress and distortion of over-torqued action screws.

The good news is that in gunsmithing they don't use torquing lubricant (unlike any other respectable machinist profession) - therefore most of the torque reading is the friction between the screw head and the pillar - which has really nothing to do with what force is actually applied to the threads, and most of the numbers are just "feel-good" remedy.

Savage Action Screw Torque Tuning within AccurateShooter.com
action screw torque setting? - PredatorMasters Forums
FERA - Case Studies - Fastener Torque and Lubrication

 

[Otero51]

Dumb question, is there a reason why torquing lubricant is not used on rifles? Would torque lubricating provide less variation between stock re-installations?

 

[Alpine Gunworks]

If you are using a black socket head cap screw those are made of an alloy steel that is slightly stronger than a grade 8 fastener. For a 1/4-28 socket head cap screw the torque should/could be as high as 192 in-lbs. Not sure you really need to torque it that hard but the fastener can take that much without damaging it. If lubrication is used the torque should be 15% to 20% lower. If it was a chassis and it was designed correctly you could easily use 65 in-lbs. If the stock isn't a chassis it all depends on the bedding and if the pillars were installed correctly. I just make sure my action screws are tight and they are not going to loosen up. My rifles shoot tiny little groups and I've never paid attention to details like torque specs on my action screws.

 

[E. Bryant]

I'd worry less about the action screw, and more about the action itself. There are not many engaged threads, the material is softer than the bolts, they can wear over time, and they are much tougher to repair than a worn screw. A much better approach for those that constantly remove the action from the stock/chassis for whatever reason would be a semi-permanent installation of studs (much as we do on any serious internal-combustion engine that is intended to be regularly serviced/rebuilt), but I've yet to see that done on an R700 (but some rimfires use similar schemes to varying effect).

I always put a bit of light oil on the action screws just to keep the thread surfaces happy. I typically don't reduce the torque spec unless I'm using something "special" (such as ARP's moly thread lube), but I've also started to use 55 in-lb instead of the traditional 65 in-lb out of respect for the aforementioned action threads.

Action screw torque depends heavily upon the quality of the interface between the action and the stock. Systems with traditional bedding can be very tolerant of variation in screw torque; I've personally had some embarrassing mistakes in this regard and have been surprised at how well some rifles have shot with action screws that were barely hand-tight. Stocks and chassis that depend upon bedding blocks can be particularly sensitive to screw torque - especially those that "float" the rear tang.

 

[SporterII]

Dumb question, is there a reason why torquing lubricant is not used on rifles? Would torque lubricating provide less variation between stock re-installations?

Simple answer to this question.
Lubricant will help transfer the torque more efficiently into clamping power by reducing mechanical friction and therefore losses. Lubricated figures are standardized to differ from dry and treated / plated figures. Chrome plated hardware dry is quite well lubricated. This is why Alpine has his reply and this is how I assemble many different types of assemblies. Often I need to cease before a specific number is achieved.

 

[Dickd]

If you will call the Remington, Winchester and Savage factory service depts. and ask about guard screw torque setting they will all tell you about 30 to 35 in. lbs.

 

[lobo56]

What about an AI chassis? Torque? Do you use locktite?

 

[E. Bryant]

The last rifle I assembled with an ACIS AX chassis used 55 in-lbs on the front screw, 45 in-lbs on the rear, and no Loctite (just a dab of anti-seize). It shoots fine.

 

[FequalsMA]

I can tell you that properly bedded rifles with pillars are not temperamental to torque differences. Once the bolt bottoms out there is no more rotation available unless you try to break something.

 

[Bender]

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