22lr Speed drop Factor.


Jesus 1st, Family 2ed, Shooting 3rd
Full Member
Sep 7, 2020
Ontario, Canada
I have a thing for quick intuitive ways to manage data. The Speed drop factor is one of these that along with your wind number can be very fast and effective. But what about 22lr?
If we look at CF it works out nicely with each additional 100 yards adding 1 mil of drop but we all know 22lr is.... well slightly more. If we scale 22lr and CF trajectories its ×4-6 depending on CF cartridge used. E.g. 100 yards with my 22lr is the equivalent of 600 with one of my 6mm.
Our Speed drop factor formula is YARDS/100-DROP= FACTOR. Well if a 22lr is approximately ×5 then 20 yards would be the equivalent of 100 CF yards. Lets try YARDS/20-DROP= FACTOR like this!

Hey it kinda works! But does it pan out in real life? The math is not quite as intuitive but still very simple. Your dialing 1 mil for every 20 yards. In this example I will use 3.4 as my factor by slipping my turret to 3.4 mil and now dialing down to zero again. Now I dial my YARDS/20. E.g 160yd = 8 mil or 188yds = 9.4 because our minds find dividing by 2 easy just take the first 2 digits / 2 and then add a 0.1 for every 2 yards in our last digit.
Screenshot_20220730-190408_Strelok Pro.jpg
Because 22lr all have very simular drop there is a simple shortcut to identify your Speed Drop Factor. Take 160yds/20-Drop-0.1. In our example
160/20= 8- 4.5mil= 3.5-0.1=3.4
This is a environmentally effected number so be sure to calculate it with your current conditions.
Now this begs the question if the Speed Drop Factor works what about a BDC? Absolutely it does. It runs along the same lines but here is the quick answer. Take 5- your speed drop factor. In our example 5-3.4=1.6 Dial up from your actual true zero (does NOT have to be 50) 1.6 mil or if you have slipped your turret to your speed drop factor already just dial up to 5 at first glance this appears to coincide with your 100 yard drop but this is not the case and will not work. Anyhow this is how it would look at two different temp with our example ammo.
Screenshot_20220730-191510_Strelok Pro.jpg

Screenshot_20220730-191546_Strelok Pro.jpg

Here Is another example with different ammo.
Screenshot_20220730-204128_Strelok Pro.jpg

This is based on usefulness for a 22lr UKD distance field match where the majority of targets run from 100-200 yards.
Some ammo you will need to start adding additional 0.1mil per 10yds at 180yds. With a bit of thought you can expand on this. But I'll leave that to you.
If your wanting something useful for hunting or 50-120 yds thats also possible but another conversation.
Anyhow I think thats it in a nutshell. Cheers
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