This was the second set of Burris base adapters that I bought from Optics Planet because they erroneously listed the first set as able to fit mini-30's, which it was not. I had to visit the Burris web site to determine the correct set of adapters and paid to return the wrong ones out of my own pocket. The correct adapters seemed to fit well except for the rear adapter which had to have a notch ground into its underside so that I wouldn't have to remove the rear sight. I also had to ground down the raised portion in the center of the adapters in order to fit a red dot scope with a large diameter lens and low mounts. This was a lot of grinding for such small adapters. The result is that now I have a very low mount that doesn't raise my line of sight more than a half inch. The adapters are made of steel but are small enough that they don't add too much more weight.
Pros: Very low profile
Cons: Requires some grindingto fit
This review was written in the old system and had content requirements that are different than reviews written today.