I have a stith mount that has a split rear ring and it work well with a 1 x 4 leupold. have you tried a tang sight ? I have the same problem ,I can't see the rear sight anymore but a peep works great
plab
Your mount with the split rear ring is a hybrid of old and new style Stiths for the Savage 99. That was not a set that left the factory that way and they are very hard to find and piece together. Johno from down under has looked for one for years now.
