If you insist on crimping, this is one of the few applications where the Lee FCD die is the only way to fly.
It is a collet die, which is operated by the shell holder shoving on it.
That makes it totally independent on exact case length, so it becomes impossible to collapse a shoulder if you get a long case in the mix.
The .223 in an AR is the most overly sensitive caliber there is to crimp with a seating die crimper.
A tiny amount of shoulder collapse, too small to see with the naked eye, will lock up an AR-15 tighter then a gnats azz.
And it is far to easy to do with a normal crimping die that is case length critical.
If you feel you just have to crimp, get a Lee FCD collet crimping die.
rc