From what I have read most of the hoopla about RL17 came from 6BR. In tests with the 6XC it did have quite a gain. It was well matched for this cartridge. That doesn't mean it is a magic powder in every application. It works in some cases but hasn't proven to offer much for most cases. Similar is Hornady's Superfomance works with some combos but not with just any bullet/cases combination.
