Let me give you an example of how much even your heart rate can have an effect on long-range shooting by a test that I did a couple of years ago...

Having one of our rifles, which weigh an average of 29 pounds, set on the bench and in shooting position (unloaded and with the bolt removed for safety reasons), using two way radio communication, we set up two 1-gallon milk jugs at 1,000 yards. With only hand pressure used in gripping the stock, with no cheek or shoulder pressure whatsoever touching the gun. With the scopes cross hairs set centered on one jug, I would radio Phil and have him move one jug while I stayed centered on the other. What I was doing was testing to see how far off target just the pulse in your hand would make the cross hairs jump. With me holding centered on one jug and the cross hairs jumping over to the other jug, there was 21 feet of movement between the two jugs with the cross hairs bouncing back and fourth between the two and like I said, this was only with me "lightly" gripping the stock...

EVERYTHING comes into play when shooting long range, espacially to some 1,000+ yards....

DAVID