Took my two Weaver Model T’s to lay in mounts with loosened top clamps, then spun them until reticule’s stayed at the same place on target at short range; that’s mechanical and optical zero (M/O zero) for the scope as the erector tube’s optics are centered in the scope tube. Both started out making a circle several MOA in diameter, but ended up with about a 1 MOA error from perfect. Blamed that small error on the tiny out of round and clearance to spin the scope tubes are spaced only about 3 inches apart. Both scope tubes are very straight; no evidence of being bent.
Loosened knob set screws then put both at zero; tightened set screws. Then moved both knobs to their limits from M/O zero looking through the scope verifying the reticle moved with each click. Here’s the results:
Weaver T10 bumped up to 16X;
...elevation - down 27 MOA, up 60 MOA; 87 MOA total range.
...windage - left 30 MOA, right 43 MOA; 73 MOA total range.
Weaver T16;
...elevation - down 11 MOA, up 60 MOA; 71 MOA total range.
...windage - left 26 MOA, right 46 MOA; 72 MOA total range.
Both have less adjustment range left and down from M/O zero. Most towards the adjustment knobs; right for windage and up for elevation. Proof to me that half way between the knob's mechanical limits is not M/O zero on these scopes; a popular belief amongst rifle shooters for all scopes.
Do your own tests with your scopes; if you wish.
Loosened knob set screws then put both at zero; tightened set screws. Then moved both knobs to their limits from M/O zero looking through the scope verifying the reticle moved with each click. Here’s the results:
Weaver T10 bumped up to 16X;
...elevation - down 27 MOA, up 60 MOA; 87 MOA total range.
...windage - left 30 MOA, right 43 MOA; 73 MOA total range.
Weaver T16;
...elevation - down 11 MOA, up 60 MOA; 71 MOA total range.
...windage - left 26 MOA, right 46 MOA; 72 MOA total range.
Both have less adjustment range left and down from M/O zero. Most towards the adjustment knobs; right for windage and up for elevation. Proof to me that half way between the knob's mechanical limits is not M/O zero on these scopes; a popular belief amongst rifle shooters for all scopes.
Do your own tests with your scopes; if you wish.
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