This is why it is important to shim the cylinder, it tightens on an o ring so it will always move a little. The fore stock is only attached to the action with one little screw, any cylinder movement caused by resting the gun on the fore stock translates to barrel movement because they are connected by the band. Shimming the cylinder will secure it far better and brace up the front of the gun helping to reduce poi shift.
Measure the gap between cylinder and action with feeler gauges, then find a shim washer this thickness to put in there.
Or as I have done many times machine the right amount off the end of the firing valve face and the same amount out of the o ring groove so the valve body face tightens directly onto the action.
HFT, for people with only 2 buttucks!
VooDoo TwoTwo The next chapter.
Last edited by Tench; 17th March 2015 at 11:03 PM.