I had no clue that my pulse through my cheek and onto the cheek rest was introducing a fairly large amount of movement until I started using higher power scopes. My groups shrank a fair amount when I eliminated the pulse movement.The easiest way to avoid pulse caused movement is to not touch your gun, other than light pressure on the trigger. For me the worst offender is having my cheek in contact with the stock You need a light trigger or an electronic one that sits in the bench. With some guns you can pinch the trigger and the trigger guard between your thumb and trigger finger and release the sear without moving the gun. Of course that doesn't work if you are required to touch the gun for whatever reason.