Looking at the load data for CFE 223 I can tell you it will be way to slow, close to BLC-2, TAC, AA2520 in burn rate.
Lead Free 5.56mm BALL POWDER® Propellant
• BALL POWDER® Propellant designed for lead-free projectiles and primers
• Propellant additives developed for barrel decoppering
Green 5.56mm BALL POWDER® Propellant
Projectile 62.0 grain, 20" barrel
Propellant 5.56mm round Velocity(ft/s) Pressure(psi)
WC 844 - Standard M855 3020 55,000
SMP® 842 - Green 5.56mm 3020 54,200
This is the powder we need(to try anyway, may not be as good as 2200), I had a line on some a while back and lost it before I could get any.
6.8mm REM SPC vs. 5.56mm M855
5.56mm M855 projectile 62.0 gr, 6.8mm projectile 115 gr, barrel 16"
Propellant Round Velocity(ft/s) K.E.(lbf-ft) Pressure(psi)
WC 844 - 5.56mm M855 2900 1157 55,000
SMP® 745 - 6.8mm REM SPC 2500 1593 53,000
•6.8mm has ~40% more K.E. than the standard 5.56mm