I bought one for a .223 I built up for a Wyoming Prairie Dog trip this past June. I liked the idea behind them and I had no major issues. I did lap the rings as a test and ended up being surprised how much lapping was needed before I mounted the scope. They look good....they are aluminum (had no problems with expansion due to heat and dis-similar metals, blah, blah, blah). I would buy another set if I needed to.......