Progressively Moving 11:00

[Zen Archery]

Did a little detail work with bullets and data.
I've shot every bullet weight (85-160gr) out of my 6.5CM

I've noticed a progressive 11:00 drift from the heaviest 160gr bullet to lightest 85gr bullet.

This is on a Thermal Scope so there's specific horizontal (W) and vertical (E) numbers. The scope is .55MOA adjustments.

85-100gr W= -25 E=-5
110-125gr W=-18 E=-10
135-145 W=-12 E=-15
150-160gr W=-8 E=-20

I fully expected vertical/elevation to change but was surprised on horizontal/windage drifted.

Anyone have background information/ knowledge base on this? Thanks in advance.

 

[HARPERC]

Tagging in!

 

[Shane Lindsey]

Not a physics guy, but I would bet it has to do with torque as it relates to the launching of the bullet. Heavier bullet less torque, less shift because the bullet is heavy/slower???

Interested to see what the smart folks say.

 

[shooter7]

Just a thought, but maybe something related to spin drift?


If the lighter bullets are moving faster they should have more rotational velocity as well and therefore maybe causing a horizontal shift? I'm not a ballistician though so I'm not sure if that would even make sense.