I have had good results with CFE223 and 8208XBR under 123 SST's.
CFE223 under 129ABLR. I have been developing all of my loads with CCI 450's
and Rem 7.5's. Go up in no more than 3/10ths increments. High strung
little cartridge, but seems to perform all out of proportion to it's size.
My bbl. is G2