Spring/Piston My TX200 Has Done it Again. . . Broke it's Scope Stop Pin

[Hoppalong Doc]

As much as I love my TX200, It broke again this afternoon. Well, not the rifle itself exactly, but the scope stop pin sheared off. I use Sportsmatch scope rings with the pre-installed stop pin (from AoA). This is the 2nd time in the 6 years I've been shooting my TX200 that its severed this pin. As I always do, prior to shooting, I tightened all the stock, trigger and scope fasteners. This time the scope moved back nearly half an inch before I caught it. This past winter I installed a Vortek PG4 full-power tune. The firing cycle is smooth and quiet, as expected. I have two other springers, a HW97K and a HW50S. What am I doing wrong? Should I be using another brand of scope rings? All my scopes are quality Hawke scopes, so I 'm not worried about them as they have lifetime warranties. So help here, friends . . . Orv.