BSA Optics TW4X20 - Manual (Page 4)

Using a Boresighter:
Follow the instructions that came with your boresighter and install the
boresighter in the muzzle of your rifle lining it up with the scope as close as
possible. Rotate the elevation knob to 1 (X100 Yards). Looking through the
scope as though you were going to shoot you should see two sets of cross
hairs. One set is a plain cross hair (this is the one in the scope itself) and
another set which is graduated or on a grid (this is the one in the boresighter).
These cross hairs should line up with each other vertically, horizontally and in
complete alignment.
If the vertical and horizontal cross hairs are not parallel with each other, adjust
the boresighter in the direction it needs to turn in order to achieve this. Make
sure the cross hairs to cross or meet at precisely the same location. Proceed
to adjust your scope right, left, up, or down until the cross hairs match.
Remove the boresighter from the muzzle.
CAUTION:
BE SURE THAT THE FIREARM IS NOT LOADED.
PRACTICE SAFE FIREARM HANDLING AT ALL TIMES.
4.) ZEROING
The next step is to test ammunition. NO two ammunitions will behave in
the same manner when fired from the same rifle. This may be one of the
most important steps in sighting in any firearm and is the one that is most
frequently omitted. DO NOT bypass this step.
• Make sure the elevation knob is set to 1 (X100 Yards).
• Holding the crosshairs steady on the target, squeeze off a round.
• Repeat this two more times to get a 3-shot group.
• While looking through the scope, set the cross on the original target.
• Rotate the windage coin adjustment until the cross hairs are level with the
3-shot grouping.
• Rotate the elevation coin adjustment until the cross hairs are in the center
of the 3-shot grouping. Once you have adjusted the windage and the
elevation, you are now ready for another 3-shot group.
Repeat this process until you are satisfied with the results.
NOTE: It is important to allow the barrel to cool down in between the 3-shot
groups as heating of the barrel can cause bullet flight to vary. It is also
recommended to swab the bore between shots with a dry patch to reduce
buildup. DO NOT use any cleaning fluid or oil on the swab as this can affect
bullet flight. Replace the windage and elevation caps.
5.) MAINTENANCE
DO NOT ATTEMPT TO DISSASEMBLE OR CLEAN THE SCOPE INTERNALLY.
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