Smallbore:stock assemply?

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tsokasn
Posts: 299
Joined: Tue Sep 11, 2007 12:22 am
Location: Athens,Hellas

Smallbore:stock assemply?

Post by tsokasn »

Hello everyone!
When the time comes for a shooter to disasssemple his rifle(barrel from stock) for any reason(a new stock perhaps),must he be aware for any asemply secrets?
Is there any specific torque that you must apply when you screw the barrel on the stock for example?
Thank you!
TWP
Posts: 384
Joined: Sun Mar 14, 2004 6:57 am
Location: Northern Virginia

Post by TWP »

Most rifle manufacturers have torque specifications for the stock screws.

Anschutz says 5nm for wood stock and 6nm for aluminum stocks.
tsokasn
Posts: 299
Joined: Tue Sep 11, 2007 12:22 am
Location: Athens,Hellas

Post by tsokasn »

Thank you TWP!
I guess a bit less or a bit more torque will affect the muzzle recoil?
Shooting Kiwi
Posts: 321
Joined: Fri Apr 20, 2007 3:33 am
Location: New Zealand

Post by Shooting Kiwi »

The Anschutz torque figures are just starting points, but don't overtighten the screws on an Anschutz in case the threads in the receiver strip! I don't know what the maximum torque allowed is. Also, more confusion, because it is not made clear whether the suggested torques are for dry or lubricated threads.

I'm sure you understand that the torque applied to the action screws determines the tension in them, hence the force pulling the action into contact with the stock. This then determines the quality of coupling of the action to the stock, and how (well) vibrations are transmitted from the action to the stock (and back again).

Torque variations will affect group size because the barrel vibration will be affected. The 'tuning' of the barrel will be altered. It is said that, with correct 'tuning', you can get the rifle to compensate for shot-to-shot muzzle velocity variation (over the small spread of velocities expected from target-quality ammunition), because the muzzle deflection will be slghtly different at the time of bullet exit for different exit velocities.

There is a lot of information around on the subject, also a lot of mis-information! Search this forum for 'barrel vibration'.
Environs
Posts: 31
Joined: Thu Nov 20, 2008 9:28 pm
Location: New Zealand (Cambridge)

Post by Environs »

Hi This is a bit of a change in subject. But which do you do fisrt: Batch test ammo to find best, then tune barrel. Or tune the barrel then batch test your ammo?
Glen
Shooting Kiwi
Posts: 321
Joined: Fri Apr 20, 2007 3:33 am
Location: New Zealand

Post by Shooting Kiwi »

Glen,

I wish I knew the answer! I think it's an iterative process, i.e. maddening and frustrating.

Tacho the ammo to find a batch with the smallest velocity spread first. I believe that takes care of the most important variable. Other variables, such as projectile mass, concentricity, dimensions, etc. can't really be tested for in .22, being ready-loaded, and the better makers can probably be trusted to have good quality control on most parameters. However, powder mix and amount are likely to be less well controlled.

When tuned, keep to the same bullet velocity (at least that's easy to test) , or go through the whole process again!
tsokasn
Posts: 299
Joined: Tue Sep 11, 2007 12:22 am
Location: Athens,Hellas

Post by tsokasn »

Thank's Shooting Kiwi!
I've got a lot of homework to do!!!
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