canting question?

[chevytruck_83]

Ive read the article in here on rifle canting and its attached articles. It all makes sense to me to a degree and has been tested through pretty extensive testing so im not debating it at all just wandering if someone can explain something.
I understand the theory and exactly how it is shown in these posts, but i cant for the life of me understand why if the scope is canted left the bullet flies left or vise versa. The chamber is perfectly round and so is the barrel and bullet ideally. So how does the cant change the actual flight? I can understand that the sight relation to the trajectory would be off but why doesnt the bullet still exit the barell and take a verticle path instead of the illustrated left or right arc?

 

[DRNewcomb]

To the best of my understanding of this subject, the bullet does travel straight out the barrel and then flies just as it would without a cant. The difference is that the intersection of the scope's/sight's line-of-sight with the flight of the bullet has changed. When you look at it from the point of view of the scope, the flight of the bullet has changed. The greater the range and the greater the cant, the greater the apparent change. This is described or drawn as a curve, which does not actually exist. Maybe someone else can explain it better.

 

[chevytruck_83]

Ok I understand now. I can read something a million times and 2% sinks in if that. I look at a picture and can build a solution very quick. though sometimes its wrong.
Upon playing with 30/60/90 drafting triangle i realized where my confusion is coming from. Looking at the picture it seems like the center lines of the bore and the scope are parrallel which naturally they are not. If you use the straight side of a drafting triangle as the line of sight representing your scope axis, then the travel side of your triangle to represent the bore of the barrel you can aim down the straight side and cant it left and right and see that the trajectory curve shifts left and right because the angle of the bore. Looking at the pic i totally had a brain fart and overlooked the fact that the barrel is slightly angled up in relation to the scope.

 

[DRNewcomb]

It probably helps to look at an extreme example of cant, like 90º. The bullet used to travel up and down in line with the vertical crosshair. Turned 90º to the left the bullet flies straight out the barrel and will cross the now vertical crosshair (formerly horizontal) and keep going to the left. Gravity will pull the bullet downward. The angle between the scope and the bore no longer gives elevation to the bullet's flight (only a constant divergence to the left). The bullet will now only drop below the line of sight, never go above. Changing cant from 0º to 90º will draw a series of impacts on the target that describe an arc.

I used RSI's Shooting Lab to compute the effects of cant and for 1-3º my other shooting errors are much greater than that caused by cant. A 3º cant should be readily obvious when you are aiming at a row of targets on a horizontal pit berm.

 

[chevytruck_83]

thanks. My error was far more simple. almost embarrasing. for a minute i chalked the bullet trajectory up as a natural effect of the bullet not that the barrel is angled up.