Back in the day I used Leupold rings and bases. One of the rings twisted in a slot in the base. Are these used anymore?
I think you are refering to Redfield jr type mounts.
Front base was a dovetail and rear base had opposing screws.
That type of mount has caused many to think they had a scope problem as the mount tends to move.
If you have twist in dovetails both front and rear that would be a dual dovetail and is a better solution.
Currently some form of Weaver cross slot is the most popular for a durable solid mounting solution.
