Thanks George never spotted that it can be changed from the pre-set "true" must look.
OK, I've looked but can't see how ??
Thanks George never spotted that it can be changed from the pre-set "true" must look.
OK, I've looked but can't see how ??
Last edited by angrybear; 30-03-2017 at 09:46 AM.
Since the Bushnell Legend isn't a Hawke scope, choose the 'Generic Mil-dot' reticle.
If you're using the latest version (V4.3.1 I think) then the calibration mag of any reticle is adjustable via the Reticle Calibration applet (Toolbox >> Calculate & Calibrate >> Reticle Calibration ... or by right-clicking on the Cal.Mag textbox and selecting the Reticle Calibration item from the popup).
If you're using an earlier Chairgun version then, once the Generic Mil-dot reticle has been selected, you can select the 'Calibrate Generic Mil-dot' (or something like that) option from the Toolbox menu.
The two applets aren't identical but they both do the same thing.
In either case, there are details in the appropriate helpfile.
I don't know why you would want to but you can do the same calculation by hand from:
C = M * T * 100 / (R * 3.6 * D)
where:
C = Calibration Magnification
M = Indicated Magnification (on scope)
R = range from scope-turrets to target (Yards)
T = Target Size (Inches)
D = Number of dot-spaces to span the Target
or, in froggy units:
C = M * T * 100 / (R * 10 * D) = M * T * 10 /(D * R)
where:
C = Calibration Magnification
M = Indicated Magnification (on scope)
R = range from scope-turrets to target (Metre)
T = Target Size (cm)
D = Number of dot-spaces to span the Target
For example:
I once had a cheapo Chinese 3-9x Mil-dot scope allegedly calibrated at 10x but disparity with Chairgun's predicted aim-points indicated that it was nowhere near. Twiddling the calibration mag in Chairgun until the predictions and reality matched, it looked more like 12x.
I found a scrap of wood, scribed two horizontal lines on it 12" apart and, with the scope set to 9x, walked towards the wooden target until the two lines were spanned by 10 full mil-dots. That happened at around 76 Feet (25.3 yards) from scope-turrets to target and measured with a surveyor's tape.
So:
C = M * T * 100 / (R * 3.6 * D) = 9 * 12 * 100 /(25.3 * 3.6 * 10) = 10800 / 910.8 = ~11.9x
George
Last edited by GPConway; 30-03-2017 at 02:26 PM. Reason: Grammar
Thanks, I'd found the bit in toolbox but no explanation as to how to use it, now found the details towards the bottom of the help file.