Steve, the .223 has a Brux 1 X 8 twist barrel. I shoot varget powder, CCI BR4 primers, and lapua brass and 80 gn berger bullets. I have these loaded with 24.5 gn varget and I reduce the load to 22.5 over 70 degrees. I loaded these to shoot in November so the weather should be fine in February. I read somewhere that brass and bullets actually bonded somewhat with time. Not sure of this, but at least I will have an excuse. WWE