From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Torquing for Tinys
Organization: Hewlett-Packard Fort Collins Site

Having epoxy bedded a friend's Anschutz 1413 free rifle, I checked it out
yesterday with several lots of Eley Tenex match ammo.  I also wanted to
find out what amount of torque on its stock screws was best to get the
smallest groups.  This lot produces about 6 to 8 fps standard deviation in
muzzle velocity.  Other lots were in the 14 to 42 fps Sd range; not good.

I first fired 15 shots to foul/warm the barrel; a typical thing to do
with .22 LR rimfire rifles.  After finding an ammo lot that showed promise
of tiny groups, I began varying the torque on the stock screws and shooting
10-shot groups in an underground, 100-yard range.  All groups were about
half-inch to three quarter inches wide.  But they varied quite a bit in
elevation.  Here's the results:

              Vertical
   Torque      Group
   in/lb       Inches
   ------     --------
     15         3.21

     17         2.73

     19         1.54

     21         0.98

     23         0.72

     25         1.05

     27         1.66

     29         2.45

Seems somewhere around 22 inch/pounds is about right.  Had I not ran out
of ammo, I would have done more tests.

I didn't think group size would change that much as I varied the torque.
Highpower rifles don't change much over a 2X range of torque.  Perhaps it
is due to the rimfire's longer barrel time and greater effect barrel
vibrations have; perhaps not........


BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: How much torque?? (Bart?)
Date: 8 May 1994 13:14:05 -0400

David A. Horton (DHORTON@as.ua.edu) wrote:

: How much should the action screws be torqued?

  * Model 70s:

      + Front and back screws to 60 inch/pounds.

      + Middle screw to about 10 to 20 inch/pounds; it isn't critical.

  * Model 700s:

      Front and back screws to 50 inch/pounds.

      Caution:  Model 700s (40Xes, too) can have their tang bent if
                the receiver is not well supported along its entire
                bottom and too much torque is applied to the back screw.
      
: How frequently should I check the torque on the screws?

You should release the torque after each day's shooting.
So, you should torque 'em up again before each shooting session.

BB