Not if you do it right.
Your JOB as a BR shooter is to provide the smoke-belching-beast with the most consistent loading you possibly can AND a perfectly repeatable path for recoil (along with a proper sight picture, etc). Any variations in your loading or the path of recoil (before the bullet exits-technically speaking) will show up on the paper.
Then you gots to dope that wind.
As I see it, stock design for a bench gun is about riding the bags and shooter comfort-in order to provide the consistency needed for good scores.
