Looks good! Nice job! Should do the job nicely. 223 ai is on my list someday. Ive just recently done my first fireforming for a 6x55 swede. Really no big deal. Im sure someone else will chime in and say which powder will do best.
Most seem to put a medium charge of the parent cartridge and seat the bullet into the lands and let her rip.
Good luck and let us know how it shoots!
Scooter