When I was sorting out my loading process for my 6.5CM rifle back in 2017, a lot of advice centered around neck sizing with a bushing to set the neck tension. So I played around with different sizes of bushing dies from .289 to .291 until I got what I thought was the right neck tension. Then after a few firings I was having a hard time closing the bolt and realized the neck die wasn’t bumping my shoulder back, so I bought a shoulder bump die w/ bushing. The rifle liked it so I stuck to that process for the last 5 years.
Fast forward to present day, I switched rifles and caliber to 6GT this fall. Being new to the caliber I did a bunch of reading to see what people were recommending. Nowadays it seems like full length sizing is the way to go, so that’s what I bought with the die set to .266 neck OD. But this time I also got a mandrel die and have been using that to set neck tension (.002 to .003” less than the bullet dia). My 6GT rifle seems to like what I’m loading up, so that’s my my process now.