I've been using 29.5 Grains of CFE 223 behind a 123 Gr Hornady SST and getting somwhere around 2550 fps out of a 20" Radical Firearms barrel (1:9 twist) and the rounds seem pretty accurate.
Hodgdon publishes some reloading data at
www.hodgdonreloading.com. Unfortunately their data doesn't include CFE 223 but there is a good variety of powders. About a year ago I was able to find data on their website for only one powder.
The "6.5 Grendel Reloading Handbook, Volume 2", available from Alexander Arms (and other sellers), has a lot of good reloading info consolidated from user submissions. Among the data there are two loads using CFE 223 behind a 123 Gr bullet:
Primer CCI 450 / COAL 2.245 / Barrel Len. 18" / Reduced Load (no data) / Max Load 31.1 / velocity 2456
Primer Wolf 223 / COAL 2.265 / Barrel Len. 24" / Reduced Load (no data) / Max Load 31.5 / velocity 2629
I based my load off of this data as well as an energetic conversation at either this website or the 6.5 Grendel forum, can't remember which.
BTW, that's another good resource for information on loads -
http://www.65grendel.com.
Last thought: I've been using both Hornady and PPU brass. Hornady takes small rifle primers and PPU uses large. I haven't seen any remarkable difference in performance between the two but something to consider with once (twice or more) fired brass.
Attached file is a five round shot group @ 100 yds.
Good shooting.