Shooting Canted – Change In Point Of Impact Trajectory? [45 & 90 Degs]

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. 

canted red dot sight shooting scar 17

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

shooting up right position eotech

Using a 16" DDM4V11 upper with an EOTECH EXPS3 (1/3 co witness sight height), zeroed 36 yards.

ddm4 v11 upper with eotech exps3

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.

36 yard zero

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.

eotech 45 degree leaning left

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.

36 yard poi 45 degree angle

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

eotech 45 degree leaning right

Shooting canted at 45 degrees leaning to the right

  • Shot group moved to the right slightly
36 yard poi 45 degrees leaning right

90 Degrees Position

90 Degrees Lean Left

eotech 90 degree leaning 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.

barricade-drill-shooting-at-awkward-angles-1

Referenced VTAC

36 yard poi 90 degrees leaning left

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

eotech 90 degrees leaning right
36 yard poi 90 degrees leaning right

Shot group moved down and to the right, overall all hits stayed within the general area of aim.

Key Takeaways

  • 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