*****need help with my leupold mk4*****
I recently purchased a Mark 4 LR/T 8.5-25x50mm (30mm) M1 Illum. Ret (TMR) and mounted it to my standard M1A. I've gone through 200 rounds of 168 gr .308 factory ammo (Nosler Trophy Grade) trying to get this thing dialed in.
When I originally zeroed the scope at 100 yards, I did so on full magnification and achieved a 1 inch shot group on center. I was hitting about 2-3 inches low at 200 yards (which is about right per the ballistics).
I have since been back to the range, because I wanted to zero the scope at 200 yards instead of 100. My first shot was 8 inches low on full magnification. Subsequent shots were all over the place (after adjustments were made).
I decided to back off back to 100 yards and re-confirm my zero. The full magnification was giving me a hard time locking down a shot group and getting on center. I decided to back off on magnification and put the scope on it's lowest power. My first three shots were a 1/2 inch group, and my adjustments to center were spot on after the first adjustment. I was repeatedly hammering 1/2 inch shot groups on center on low power.
But then I'd go back to high power and my shots would just be all over the place. The Marine Corps taught me how to shoot. I have several other scopes. This isn't my first rodeo...but what the heck is going on here? Could it be a faulty scope?
Your help would be much appreciated.