Now a rock solid mount that does not depend only on the Trackers vent rib for security. We have designed the ultimate no drill and tap mount for the Tracker vent rib style .22 LR and 17 HMR. This mount requires removing the rear sight and uses the rear sight notch as a recoil lug. It is as solid as our drill and tap model. Extra large recoil lug prevents scope mount movement . Accepts most Weaver style rings and accessories. This will NOT Work Taurus Model 66, 627, 357 mag