I've reloaded a lot of 6.5 Creedmoor and a few .308 with the Lee Collet neck die. Some rounds chamber like they should some not. I'm about to start FL re sizing on them for a while. According to everything I've read the neck size dies don't bump the shoulder back giving the hard chambering cases.

I do have a redding 3 die set for 6.5-284 with a neck die that seems to do a better job than the lee but I've noticed it needs lube or it's very rough on the up stroke of the press. I do have a set of Forster dies for my 6mm-47 Lapua I'm building but havent got far enough along to use them though.

Not exactly your situation but similar in the case of the creedmoor.