With a gun rest of any kind I can sight a gun with one single shot. I take a shot with a gun secured in a gun rest, aiming for the middle of the target, Then after the shot I look through the scope to make sure the crosshair is back to the spot I was aiming. if not I make sure its there. Then I look for where I hit the target. Without disturbing your gun anymore I walk the crosshairs from the center to where I hit using only the vertical and horizontal adjustment. You are basically looking through the scope, without touching the gun, and clicking until you move it to the spot it hit. Once your crosshair is on top of it you are sighted in.
Old timer out in Brook Haven LI taught me that trick almost 22 years ago works perfectly