In his first Gun Gack, Mule Deer says that the lab boys report the .243 has a lot of pressure issues, especially near the top end, and it gets worse when the throat starts to erode. He avoids that by staying in bounds with his loads, something I tend to do with most rounds anyway, as ranges here tend to be short. The 6 CM is thought to be a bit easier on barrels due to the sharper shoulder. I have both. The Creed is 1-7", the .243 the usual 1-10. No problem, I just organized my bullet pile and there are maybe a couple thousand, most of which will spin okay in either. Given a choice, I'd go 1-7" every time, which should spin almost anything, anywhere.
