I bought some Weaver Tactical rings (6 hole caps) to mount a scope to my Mossberg MVP. The bases are Weaver. Other rings with Picatinny mounts wouldn't work (I tried). I had been using Weaver medium rings but wanted more height. Anyway, I mounted the scope and torqued everything, without any thread locker. I had wanted to verify a couple of things at the range before final mounting with blue thread locker. Two things happened. After only about 60 shots (5.56x45) all 6 screws on the right side of the rifle were loose. And when I removed the caps there was a scratch line along the scope tube right where the part lines of the caps to bases were located, 4 places on the tube. That did not happen with the old Weaver rings. However, I think I mounted the scope to those rings with blue thread locker. I don't recall anything getting loose.
I torqued the ring caps and measured the diameter to be 0.981 inch. The tube OD is 0.997 inch. So there is negative 0.016 inch clearance between the tube and rings. With the tube laying in the ring bottoms and the caps firmly on the scope (but not torqued) there is a slight gap between the tops and bottoms, as expected.
I am guessing that the scratches came from the screws working loose and not because of ring defects. However I'd like the experts to weigh in. And I think the scratches are purely cosmetic.