Effects of Cant

by
posted on May 24, 2018
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
effects-of-cant.jpg

From the June 1955 issue of American Rifleman, a question and answer session reviewing the effects of cant.

While I have seen answers giving the effect of cant for certain cartridges at a given range, I would like to have an explanation which will be adequate for determining this effect with any cartridge at any range.—George A. Williams, Brooklyn, NY.

Answer by E.H. Harrison: The effect of canting the rifle in firing is to move the impact of the bullet on the target in the direction of the cant, and also slightly downward.

Effects of Rifle Cant
The above illustration shows in perspective the effect of cant when firing at a vertical target with its center at the point T. The gun is at G, and the line GT is therefore the range. Because of the curvature of the trajectory resulting from gravity, the bullet must be discharged at an angle above the line to the target, and in the figure the point toward which the bullet must be discharged is P. If, for example, the rifle is canted to the right, the result is to discharge the bullet in the direction of the point P′. This obviously will result in the bullet striking to the right of the center of the target and also slightly lower. The latter effect is trifling and can be ignored, and the important result is to move the strike of the bullet from T to T′. We see that the magnitude of the effect is dependent on both the angle of elevation (which governs the height PT) and the angle through which the rifle is canted.

We can determine the total effect on the target from the magnitudes of the above two factors. PT obviously depends on the range and the angle of elevation. The sportsman seldom knows the latter, but he can obtain PT from the approximate relation that it is four times the midrange trajectory height. Trajectory heights for various factory loads at ranges up to 300 yards are given in factory ballistic tables. For example, the midrange height of the factory .270 Winchester 150-grain load when shooting at 300 yards is 7.8 inches, hence the height PT under those conditions is about 31 inches.

For the effect of the angle of cant C, note that the distance TT′ (which is the displacement on the target we are looking for) is given by the relation TT′ = PT sine C. The values of the sines of angles 1° to 6° are:

Effects of Cant | Sine
If in this case we cant the rifle 5° to the right, the displacement of the hilt will be 31 times .087 or about 2½ inches to the right.

In the above way the effect of cant can be readily computed for any cartridge of known ballistics. We see that at long ranges or with cartridges giving quite curved trajectories, the lateral displacement on the target can be considerable. This is notably the case with the .22 long rifle.

Latest

CMP Dday 2025 1
CMP Dday 2025 1

Results: 2025 CMP Talladega D-Day Matches

Chance Cavin sets three new records, while Kirschenmann, Schachle and others shine at 2025 CMP D-Day event

NRA High Power Mid-Range Championship Debuts in Oklahoma

National records were shattered and new champions crowned during the 2025 NRA High Power Rifle Mid-Range Championship’s successful Oklahoma debut

NRA World Shooting Championship Awaits SSSF’s Top Gun Athletes

SSSF’s Top Gun Challenge sends six athletes to NRA World Shooting Championship after standout performances at 2025 SCTP & SASP Nationals

New: Smith & Wesson Model 1854 Stealth Hunter Chambered in .45-70 Gov't

Smith & Wesson adds .45-70 Gov't chambering to its Model 1854 Stealth Hunter lineup

Taran Tactical Comes to VR: Ace Virtual Shooting Partners with Hollywood’s Gun Trainer

Ace teams up with Taran Tactical Innovations to bring Hollywood’s favorite shooting range and guns into VR—including a lifelike TTI Sand Viper replica

WATCH: Hillsdale College Building a Legacy in Shooting Sports at Halter Center

Hillsdale College supports collegiate shooting sports with superb facilities and student-athletes competing in shotgun, pistol, rifle and action shooting disciplines

Interests



Get the best of Shooting Sports USA delivered to your inbox.