Not compatible with fastfire iii red dot - Ruger Weaver-Style Scope Base Adapter for Mark I, II, III Pistols 90224

All was good until I mounted my new Burris Fastfire III red dot sight. The grooves that run across the Weaver style base adapter are not deep enough to fully accomodate the bar acrossthat runs across the clamp of the sight. The sight rocks back and forth and will not sit fully flat on the adapter. I had to file a groove about 20% deeper (1/2 hour job) to get the sight to sit flat and not rock foward and backward. Other base adapters I have used did not pose this problem.
Pros: Nice finish, mounts easily
Cons: Grooves across rail not deep enough

This review was written in the old system and had content requirements that are different than reviews written today.