Yes. Usually more on AR's than bolt guns from my experience. Not only can it change your zero but also muzzle velocity change is worth noting for the longer range shots.Too bad its not like that here... BTW, do you see a shift in zero when you put the can on? I only ask, b/c When we did M-110 training w/ the Knights Arm. Semi Auto Sniper Systems, after a 300 meter zero, w/o the can... We put the cans on, and every single one had about a 6 in shift, on the 300m target.. So we had to have DOPE with and w/o the cans, in our data books. Just asking what you have seen shooting w/ a can.