Canting a rifle

Ed-WI · Post by **Ed-WI** » Mon Jan 25, 2010 10:48 pm

If an air rifle is sighted @10 meters with no cant, what effect would say a 15 degree cant have on point of impact? Anyone know of any data? I would expect that the sight height above the bore would also effect this...

Soupy44 · Post by **Soupy44** » Tue Jan 26, 2010 1:16 am

I don't have the info with me to do this completely out. But if you find out the radius of the circle made by shooting the rifle on all 360 degrees, the pellet will impact at .964 times the radius on the vertical, and .265 times the radius on the horizontal.

This is assuming the pellet travels in a straight line, there are no significant decelerations or ballistics, and that I did my math for the unit circle correct in my head (it's been a while). I feel that's assuming a lot, so hopefully someone with paper and pencil can work on this.

Gerard · Post by **Gerard** » Tue Jan 26, 2010 2:25 am

Read the following documents on the effect of rifle cant on the point of impact :

http://home.wanadoo.nl/jhogema/skeetn/b ... ntel1e.htm
http://home.wanadoo.nl/jhogema/skeetn/b ... ntexp1.htm
http://home.wanadoo.nl/jhogema/skeetn/b ... antlos.htm

Happy reading !
Gerard

daisy · Post by **daisy** » Tue Jan 26, 2010 6:34 am

Here is a demo that shows cant angle to impact.

http://www.arld1.com/impactpointvscantangle.html

HTH
Daisy

Ed-WI · Post by **Ed-WI** » Thu Jan 28, 2010 1:15 am

Thanks a lot everyone. Very informative & I will be reading this more thoroughly. Cool simulator too!! Very surprised that sight ht does not have an effect.
Thanks again,
Ed

NateG · Post by **NateG** » Fri Jan 29, 2010 1:46 pm

Ed-WI wrote:Thanks a lot everyone. Very informative & I will be reading this more thoroughly. Cool simulator too!! Very surprised that sight ht does not have an effect.
Thanks again,
Ed

In order to hit the target, the bore has to point at a point directly above the center of the target, where the distance above is equal to the ballistic drop at the target range. Since the sights are zeroed, then the sights are pointing at the center of the target. If the barrel and sights rotate, the point the barrel is now pointing at is no longer the spot directly above the target, but in a circle around the target, centered on the center of the target, with radius equal to the drop of the projectile. Since the sight height doesn't effect where the barrel must point (though it would change the elevation angle needed to point at the correct spot), it doesn't change the effect of the cant.