Hand tight switch barrel

[DangerRanger]

I have watched thier videos on this.
This is the kind of BS that passes for engineering in today’s manufacturing sector..

Oof.

You’re not talking about Accuracy International I would hope?

 

[rickt300]

Pretty sure you need to think inch pounds, foot pounds is way way too much and can/will damage barrel nuts. Speaking of the nuts they are generally pretty thin pieces of metal and I think anything past 60 inch pounds is getting into the point damage may occur.

 

[DangerRanger]

Pretty sure you need to think inch pounds, foot pounds is way way too much and can/will damage barrel nuts. Speaking of the nuts they are generally pretty thin pieces of metal and I think anything past 60 inch pounds is getting into the point damage may occur.

I do not think anyone in this thread has mentioned a barrel but.

 

[rickt300]

I do not think anyone in this thread has mentioned a barrel but.

Oops my bad I just took it for granted, still it is inch pounds not foot pounds.

 

[rardoin]

Oops my bad I just took it for granted, still it is inch pounds not foot pounds.

Sorry but 40, 60, 100ft-lbs on proper
Barrel threads will NOT cause damage.

 

[eric32]

Accuracy international is the exception to the rifle rule of torque. That's due to the sheer clamping force and load the quickloc puts on a barrel.

Hand tight is fine but a extra/additional force is need to clamp the barrel from movement during the actual firing processes that produces the harmonic vibrations in the barrel

 

[F Class John]

Hand tight works until it doesn’t. Ask me how I know...

80ft/lbs with a torque wrench every time on my Defiance now.

 

[Texas10]

I am having a barrel spun up for me with a wrench flat on the end to tighten. I was thinking of just having them do away with the wrench flat and screw on hand tight. Does this affect accuracy?

You need more than just a barrel seated against the action, you also need proper thread engagement and you can't get that with simply hand tight. Without good, intimate thread engagement, you'll never get good, repeatable harmonics moving from barrel to action and back, and your groups will show it.

 

[expiper]

I dont use a torque wrench ,,,but give it aprox 50-60 ft pounds,,,,nice and snug ,,,never hand tight !!!,,,at the super shoot a top competitor started shooting poorly and he realized that he had forgot to tighten the bbl with a wrench ,,in the rush to change bbls and reload he only hand tightend his bbl and it ruined his day,,,

 

[jackieschmidt]

Pretty sure you need to think inch pounds, foot pounds is way way too much and can/will damage barrel nuts. Speaking of the nuts they are generally pretty thin pieces of metal and I think anything past 60 inch pounds is getting into the point damage may occur.

75 inch pounds is not even 7 foot pounds. Think about that.
Barrel nuts such as Savage are machined from Alloy Steel with sufficient strength to withstand the proper torque when securing a barrel.

 

[jackieschmidt]

You need more than just a barrel seated against the action, you also need proper thread engagement and you can't get that with simply hand tight. Without good, intimate thread engagement, you'll never get good, repeatable harmonics moving from barrel to action and back, and your groups will show it.

The problem arises when shooters lack understanding of exactly how a threaded joint works.
By threaded joint, I am referring to the process of bringing a male and female thread against a preset shoulder with Sufficient tightening to place the parts in proper tension so that the mating parts cannot move under normal use. typical applications are engine head bolts, connecting rod and main bearing bolts, high pressure flanges, etc.
Other threaded joints, such as a micrometer spindle, serve an entirely different purpose.

It’s not about harmonics in the mechanical sense. Keep in mind, all threads have to have clearance in the pitch diameter in order for installation. This normally comes to between .002 and .003 difference between the pitch diameter on the male and female thread. If your barrel can shift in position between shots, it will show up on the target.

Granted, on a rifle that is involved in a Discipline where it makes no difference, then perhaps it becomes a moot point. However, in most Benchrest applications and other Disciplines that require extreme accuracy, it can prove to be disastrous to the aggregate.

In many industrial applications, the term “torque”;is an arbitrary figure. In many applications, bolts and other joints are secured by actually stretching the bolt to a predetermined length, then seating the nut, and releasing the pressure So the holding force is in direct relation to the tension applied by the fasternerl

 

[jackieschmidt]

Oof.

You’re not talking about Accuracy International I would hope?

I am talking about anybody that tells you two small set screws are sufficient in properly securing a threaded joint where the purpose is to allow zero movement between the mating surfaces.

 

[Dgd6mm]

So Curtis/terminus not AI

Jackie answered your question. He said Anybody.

 

[DangerRanger]

Jackie answered your question. He said Anybody.

He said he watched their videos and I was trying to clarify who “they” were

I will delete my post since it seems like we don’t want to use names

 

[SPQR70AD]

would the rifling twist of the barrel keep it from coming loose as the bullet goes down the bore

 

[lukehalee]

OMG!
I just watched the Zeus quick change barrel video. All I can say is I hope the people I’m competing against at benchrest matches start using actions with these features!

 

[jackieschmidt]

Accuracy international is the exception to the rifle rule of torque. That's due to the sheer clamping force and load the quickloc puts on a barrel.

Hand tight is fine but a extra/additional force is need to clamp the barrel from movement during the actual firing processes that produces the harmonic vibrations in the barrel

The Accuracy International System is much more than two set screws binding against the thread tenon.
Their system actually clamps the action thread firmly around the barrel tenon after it is seated against the shoulder. In affect, this results in a interference fit on the threads pitch diameter which would be impossible to assemble without the clamp/release feature.

 

[eric32]

I owned one for a while, they are awesome too bad that is a patented idea and they won't let it go.

I completely understand what is needed, i was making the point without an external clamping force its just a bad idea for hand tight. The curtis customs idea of set screws was a gimmick.

I will be utillizing barrel flats on my stiller barrels and a crows foot and torque wrench for field barrel installs.

You can hold a buttstock in your feet and snap on some pretty decent force with a wrench.

 

[Brians356]

On my Savage which is a switch barrel I have found 40 ft.lbs. to work fine.
Remembering that I have some anti seize on the threads this 40# translates to different numbers with different substances applied to the threads. There are published lists for torque reductions when using different substances. The reduction amounts are quite surprising. (minus 50% with some).
What I have found difficult is to get a manufacturers torque value that states the value given is either 'dry' or with a particular substance.
ARP in the automotive world has no problem providing it and it is of course with their product.

Stands to reason that, absent a specified substance, one must assume "dry".
-

 

[M-61]

Your quote:
"In God we trust. All others bring data." W. Edwards Deming"

I'll go with the above. I don't think lacking data means one must assume anything.
It means more research to find the 'specified substance'.