Friz,
I agree, sounds like hunching down on the rifle, almost like shooting prone.

Best to sit more upright.
For heavy magnums we use the rule " back straight and belly touching the bench." Takes about 6 to 12 sandbags which really makes you " look different" -- don' t care. If they won' t let you use more sand bags then bring your own.

Sit upright, get that thing sighted in and get off of the bench!
EKM