If you did not bring your die down to touch the shell holder with the ram all the way up and then add a another 1/4 turn to the die before locking it down. Then you more than likely did not get your case sized enough.
I shoot 223, 308 and '06 in service rifles for High Power and John C. Garand matches and have not had to use small based dies for any of it. Out of the three, 223 needs the extra 1/4 turn on the die the most.
God Bless our Troops especially our Snipers.