I have to this point loaded rounds to 223 specs based on Hornady and Lyman load data. Hornady has 5.56 data and I was considering loading some of their 75 grain HPBT bullets to 5.56 charges using CFE 223 and/or TAC. My rifles are both chambered in 5.56 so that won’t be a problem. I’d be interested to hear from anyone who loads to 5.56 specs and if it causes any issues or you have to stop short due to pressure?