Strelok pro has a trajectory validation feature. I don't have a chrono, so I used this feature to true my velocity. It works by applying your actual drop at distance to adjust either your velocity or BC, your choice.

I chose velocity because my 20" barrel length is a bit less common.

In the App, press the icon at the bottom right of the main screen for your setup. It is an arc hitting a target with an up/down arrow.

Plug in your actual drop and it shows you the velocity (or BC) to use.

I use the ballistic X app to accurately measure drop from the center of the group being measured.

After doing this. I was dead on at 200 and 300, but I don't have access to a longer range yet to fully test.

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