Erno86, having worn out 3.5 30 caliber magnum barrels and each one's had 60% of the rounds through them fired using a scope, I can clearly see the outside edges of the recicule twist as the round fires. Isn't very much, but it can be seen with 13+ pounds of rifle and scope after firing a 200 grain bullet out at 2950 fps.
That torque coupled with the reward recoil that causes the muzzle to rise all contribute and the whole rifle moving about a bit while the bullet's going down the barrel is what makes magnums harder to shoot accurately off the shoulder.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master