The Burris rings with 0 inserts work. If youre concerned about crushing take to the outside of the inserts with sandpaper, but its not necessary. The original style Weaver 1" can be used if you fit them carefully and dont screw them up too tight. Again, if youre worried about crushing, you only need to "flatten" the top of the bottom of the ring set a tad so that the scope sits perfectly. Weaver also made the same original type rings in 26mm, but will take some finding. Or I have a set of Delrin inserts for 30mm rings down to 26. Barely noticeable unless you look closely, and to make it even tidier, trim off one end of the inserts so that they fit flush to the ring.
Or, fit PH bases to your Thompson and use original PH26mm rings, theres a few sets floating around if you put the word out.
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