Could my rings be too tight?
 

I used to be able to light matches at 100 yards with my Knight MK85 setup. A couple of years ago, I bought a NE Arms Ultra Slug gun and was astonished at the accuracy with Lightfield slugs.

Then about 2 years ago, everything changed - my groups at 100 yards are all over the map. The only difference was I put new Warne scope rings on both firearms that have the torx head screws. Both have rather expensive Redfield Illuminator scopes. Because I can really tighten the torx screws down, I'm wondering if it's possible to get them too tight on the scope tubes and cause some negative affects on consistancy? Thanks.

Make sure that your rings are not closer than about .75" to the adjustment turrets.

You most certainly can tighten rings to much. Seen bent tubes due to over cranking.

Other things to check:
- objective(bell) to barrel clearence
- Visually inspect the scope tube for denting or marrs other then typical ring contact
- Rings are tightened evenly (installing rings is like installing tires you want the same torque or pressure on each screw) Check the gap or spacing on the top of the warne rings to see they are similar
- Bases are in fact snug and not bottomed out on the receiver. When I install bases I screw in the base screw by themselves counting the revolutions till bottomed out. When attaching the base I count the revolutions to ensure its not bottoming out prematurely.
- Swap out scope or rings (then vice versa if problem isn't solved)