Was this a rifle known for better accuracy with another scope? Some rifles and ammo combinations are only going to give you 1 1/2" accuracy. You could have a defective scope.
When I bought the rifle I installed a 1-4x24 Millet I had lying around unused, consistently shot .7 MOA groups with it (with 4x!) I still have the targets. Unfortunately I sold the scope so I can't put it back on to try if accuracy improves.
But its clearly parallax, I have a 4-16x44 Meopta Tactical on my target rifle, it has a parallax adjustment, no matter how I look through the scope the reticle doesn't move at all and my best group is pretty much one ragged hole with 5 shots of my handloads.
By the way, thats a really nice looking rifle!