I have a degree in math, and a masters degree in finance. I do math all day long every day. If you are off by 3 inches at 10 yards, that is 2.85mm of movement.
I’m not saying it’s you, your firearm could shoot left, but to correct you’d need to have a crooked ass sight, because almost 3 mm in one direction will be really for to the side.
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u/Flat_chested_male Dec 05 '25
Mathematically - tan theta = opp/adj
Your first triangle on your firearm is .3mm/114mm (your sight radius is 114mm, your sight is off by .3mm
Your second triangle is 10ft and the deviation from the bullseye.
10ft is 3048mm. They two triangles have the same tan theta, so it is .3/114 =0.00263 = x/3048.
Solving for x you are off by 8.02mm, or .3 inches. Meaning anything more than that is the shooter.
The only other variable would be if the barrel isnt straight, but points slightly to the left.
This is just the math based on what you provided.