WTS T'SOB base & (I believe) Weigand rings) from my former FA 83 in 454. The orginal cross bolts for the rings were soft and had stripped heads when I got them, I drilled out and retapped for larger screws, and opened the cross slot in the base with a small round file just enough to accept them. I also cut the front ?inch? off the T'SOB to mount my larger objective scope farther back, & broke the sharp corners at the front & rear.
This setup was rock solid with 300 xtps at around 1600 fps (pretty snappy).