Need a little feedback. I bought a Savage 10/110 Trophy Hunter XP with the Nikon BDC scope and wood stock - brand new. I went to the range and got out the lead sled to zero the rifle. It was bore sighted from the factory and after a couple of shots I had it on paper at 100 yds. I then proceeded to try and zero the rifle. I couldnt get better than a 6" group size. Shot through a little over a box of ammo. Came home and check the scope mount and the rings were not remotely tight. Tightened them up and went back to the range. Lead sled again and this time really took my time between shots. Also brought out a different brand of ammo to try. It shot better but still around a 4" group was the best I could get it to shoot (3 shots) and every now and then it would shoot way off. I mean like a foot off the others? ? Only happened 2 times out of 20 shots. Does anyone else shoot this rifle? What group size should I expect to get at 100 yards? Should I start by buying new scope mounts? Does anyone have any idea why it would have those shots that went way off target?

Ammo was winchester Super X 180 grain
and Fusion 165 grain

Thanks in advance