Once you have zeroed your primary optic in the upright position, does the bullet's point of impact change when the optic is canted and the bore axis position has shifted?
We've tested this and here is what we discovered with standard 55gr 5.56mm rounds.
All rounds hit within the combat effective zone, but POI has definitely shifts due to angle change
Cant error increases as distance increases
Optic height does add error to POI
Up Right Position
Point of aim using the center 1 MOA dot is the center of the diamond.
The point of aim is the point of impact using standard 55gr 5.56mm rounds.
45 Degrees Position
45 Degrees Lean Left
Note: This is NOT an angled offset red dot sight, it's a primary optic mounted on the top rail.
When positioned the rifle's primary optic at 45 degrees or other variations of center axis relock shooting positions, here are the results at 36 yards.
The point of aim is still the center of the diamond.
- Shot group slightly moved to the left and stayed within the size of a CD.
45 Degrees Lean Right
Shooting canted at 45 degrees leaning to the right
- Shot group moved to the right slightly
90 Degrees Position
90 Degrees Lean Left
When positioned the rifle at 90 degrees shooting from a stabilized position, here are the results at 36 yards.
This shot group data is interesting for shooters who are curious about what the bullet does when shooting under a barricade or a car while using a red dot sight at 90 degrees angle.
Shot group moved ~2" down, and ~1.5" to the left. Overall all hits stayed within the combat effective zone at 36 yards.
90 Degrees Lean Right
Shot group moved down and to the right, overall all hits stayed within the general area of aim.
- Point of impact shifts slightly as the bore axis shifts when the aiming the primary optic canted at the target
- Combat effective hits for mid range & close up distance for a IPSC or a human torso target
- Canting effect on point of impact increases as the target distance increases
Check out this detailed article about this topic written by riflescopelevel.com