Rifle Canted Scope Angle – Effect On Point Of Impact

Many people believe they will never have to shoot their rifle at a 90 or even 45 degree angles, but it is a skill worth practicing. In the same way that you may never have to use a gas mask in your lifetime, but it is still important to know how to use one in case you need to.

Canted scope when holding a rifle sideways can still be accurate at close to mid range distances. We've tested this and here is what we discovered regarding point of aim vs point of impact with standard 55gr 5.56mm rounds. 

All rounds hit within the combat effective zone, but POI has definitely shifts due to scope cant angle change

Cant error increases as distance increases when holding rifle sideways

Optic height does add error to POI

Up Right Position

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

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 Canted Shot

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 Holding Rifle Sideways

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.

Referenced VTAC

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.

FAQ

Why Shoot Off Angle?

There are many reasons why you may need to shoot your rifle at a 90 degree angle. For example, shooting under an obstacle for cover like a vehicle, or staying behind cover with a small window of opportunity may require an off-angle shot.

Additionally, trying to keep a lower silhouette in a concealed or urban scenario reduces your size signature. An upright position makes you more vulnerable unless you don't really care where a cannon position can give you a slight advantage.

The Trajectory Path

The projectile first travels upward towards our point of aim on a vertical angle before it descends back down the rest of its flight out to further distances. 

If we were to fire upright, then we get an impact as expected. But when we fire with the exact same point of aim this time at 90 degrees, we may get a miss depending on the zero distance we chose.

Mastering Shooting Off Angle

Shooting off angle takes training and practice, especially when using a shorter zero distance. Set up a similar target and track your impacts in real-time so that you can make predictable impacts in the event you have to take this rare shot in an emergency. 

Key Takeaways

• Point of impact shifts slightly as the bore axis shifts when the aiming the primary optic canted at the target

• Still achieves combat effective hits for mid range & close up distance for a IPSC or a human torso target, so no need to compensate for shooting angle much

• Canting effect on point of impact increases as the target distance increases

Check out this detailed article about this topic written by riflescopelevel.com