Message-ID: 
Newsgroups: AIRGUN.LIST
Some Pc and Co2 gun change harmonics as they grow and shrink under pressure,
causing lateral as well and vertical shifts.
try some rubber "o"rings or wedges in several places along the barrel 
between
tube and barrel).  ld
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Garry L. Teeple wrote:
> I have been trying to determine why a group shifts from right to left as
> either heavier pellets are used or the charge drops.
>
> I keep missing sparrows at beyond thirty yards which I was blaming on the
> wind when using my QB77.  I moved to the basement this past week and shot
> a lot of five shot groups using various pellets.  The main difference is
> the impact location of the group which for the most part is inline with
> the weight of the pellets.  Lighter pellets hit about 1/4" high and 1/4"
> to the left.  The only exception to this is Mako pellets which also hit
> 1/4" high and 1/4" to the left.  Shooting Premier lights until the CO2
> starts getting week I leave a neat line from 1/4" high and 1/4" left to
> 1/4" low and 1/4" right.
>
> The only thing I can see is that the scope is mounted slightly to the
> right of the receiver.  Is this the cause of the group shift?  If so how
> do you go about mounting the scope centered when you are using clamp on
> mounts on the machined dovetail slots?
>
> It's only when you get hold of an accurate rifle that these things come to
> light.
>
> Garry
> Mid-MO
>
> --
>  (Garry L. Teeple)
>          AirPower Information Services BBS * 610-259-2193
>       http://www.airpower.com  Telnet://airpower.dyn.ml.org
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