Thread: Aim with variable power scope?

Hi,
I wrote an article on this for NZ Guns & Hunting a few issues ago. Here is an extract from that article. I was demonstrating the use of a cheap MILDOT scope on a 22LR being used to shoot out to 200m without needing to dial the scope. The exact same principle applies for what you want and the formula still works if you want to use 16x and your MILDOTs. You will need to rearrange the equation below to make it work out what you want it to.

The formula to work out how much to reduce the scope power is a straight forward ratio:

SPR = (SPA × A) / HOR

Where
SPR = Scope Power Required
A = Aiming Point Hold Over
SPA = Scope Power where the hold over is correct
HOR = Hold Over Required

For my example I want to use the 4th mildot under the centre of the cross hairs – this mildot is 4MIL at 9x power. This means for my example “A” is 4MIL and “SPA” is 9x power.
My ballistic program estimates I will need 5.4MIL of elevation to hit a target at 150m. Using the above formula this means to use the 4th mildot I need to reduce the scope power to 6.7x power (9x4/5.4 = 6.7).

DISCLAIMER!!!
You need to test this theory on your rifle and your scope. I have no idea if your scope

• has a correctly dimensioned reticle at the nominated magnification
• that your scope actually magnifies the image the amount is says i.e. it is 16x when it says it is, and all the other power line up as well
• that your scope does shift its point of impact when you change the scope power.