Originally Posted by Jim_Conrad
Thats interesting. In my .221 AR, CFE BLK runs around 400 fps faster than 1680.

While I load for a 221FB in a CZ, I haven't tried any CFE BLK yet. But take a look at the burn rate charts in the following two links, and note the positions of Win 680, Accurate 1680 and CFE BLK relative to each other. Of course, the caveat applies that all powders can and do shift positions on a burn rate chart depending on their application in different cartridges.
Ramshot/Accurate Burn Rate Chart
Hodgdon Burn Rate Chart

Pursuit may be, it seems to me, perfect without possession.
Robert Kelley Weeks (1840-1876)