It's not offered in any factory rifle anymore. It is considerably faster than a 223, it will beat a 22-250 by roughly 150fps. If you do buy it you may run into trouble with light bullets, the wssm came out with a 10 twist barrel, I had problems with the light varmint bullets disitegrating mid air. I have a super shadow, light little gun and it is pretty accurate with the 53gr tsx. It also pushed the 75gr vld well.
What model is the rifle you are looking at? push feed or controlled round feed?