Do you ever have days when you shoot well and others when you're not shooting well? I recently sighted in my 300 WM Sendero w/Leupold M1 4.5 x 14 and I could not get it to group very well at 100 yards. I was pretty distraught. I did some research on parallax and found that it's critical to have your scope focused PERFECTLY or your reticle will move in relation to the target as your head moves. I went out yesterday and put the rifle on sandbags and focused the scope. Even though it looked focused, I moved my head around and found that the reticle moved on the target, so I adjusted my focus knob until the reticle was locked on the target when my head was moving. Consequently, I shot my best group yet (5 shots @ .70 inches). I did the same thing with my .308 and shot about the same group which is my best yet. I found a cool little white paint pen at a hobby shop and made a dot on the focus knob that shows when I'm perfectly focused at 100 yards. Hope that saves someone some unneccessary frustration.