April 3, 2014

.22lr basic ballistics

Remember that annoying stuff from high school called algebra? it comes in handy for finding out how much I need to adjust my scope for at a given distance. 22lr is a dinky cartridge in terms of long range shooting. It drops off fairly quickly, so how do I know that, given proper conditions (ideally in a vacuum) what MOA to set my scope at?

When I analyzed the graph of a 40g load CCI mini-mag, I noticed that Excel couldn't accurately portray what was going on between 25 yards and 50 yards. However- from 50 yards to 250 yards the data could be represented accurately with the following equation:

[ Y= (-0.122x^2-3.7842x+0.6411)/50]

Where the variable 'X' is your distance. Simply plug a number in for X (your distance) and the equation will tell you, 50 yards and beyond (guaranteed up to 250 yards) what your MOA drop will be. Handy. As for 0 yards to 50 yards:

[ Y= -1.2x^2 + 4.8x -3.6/50]

The graph for 0y-50y isn't precise, but it should give you an idea of how to adjust your elevation. Know that at distances closer than 50 yards, your bullet will rise.

This equation assumes that 50 yards is your zero. Doing some backwards math, and assuming that my Simmons 22mag scope will adjust 30 MOA in either direction, The maximum effective adjustment range for a Simmons 3x-9x by 32mm scope is approximately 140 yards.

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