Although the dovetail rails on air rifles are all similar there is no absolute standard and it is very rare that the mounts are actually an ideal fit. Try fitting both mounts together on the back half of the action, one with the clamp screws on the left the other on the right. Any misalignment shown will be double the actual amount the mounts are off centre when fitted. Centre split mounts like BKL can improve the centring of the scope. On some mounts the clamp shoe can be fitted either way up to accomodate different width rails. try to position this so the bolt face is as close to square as possible other wise the clamp can tip the mounts sideways when tightened.
HFT, for people with only 2 buttucks!
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