I wasn't able to find any information on these rings.
However, I do have a set of adjustable Barrett rings. They are TALL, from the top of the dovetail flat to the bottom radius of the ring is a close 1". The length of the rings are around 1.2", kind of long and the rings are aluminum with steel phosphate coated torx head cap screws. Four screws per cap, two screws for the vertical tilt/slope adjustment, and one crossbolt to lock the ring itself to the base. They do not come with 1" inserts and I think the rings have a 2 degree adjustment. Price runs $180 from Barrett, perhaps it will be cheaper if you know a dealer.