Almost positive those Seekins rings wont even fit a weaver rail. The lug that runs across the bottom through the slot in the rail is wider than the spec on a Weaver rail. They are made so that they fit almost snug in a Picatinny rail with little slop. (I ran into this problem specifically using weaver rail and seekins rings last year) You would have to jam them in the slot and use the screws to tighten them in there, which would pretty much ruin the rail and probably leave the rings cocked slightly due to the material you had to shave off the sides of the rail slot as you tighten (or vice versa). If they fit a Weaver rail, then the rail was out of spec which is probably pretty common too. But... you likely have a picatinny rail on there if they easily sit flat. Its super odd that those rings dont snug up though. Never had that happen. My bet is the issue is the rail, and not the rings. If you carry a ring into a gun store ask them if you can drop it on an AR15 on their display rack. They should have pic rails already so there would be no need to open a box etc.