Definitely 1-8". Brux will do a S/S in a #3.....that's about as heavy as I would go. A Bartlein #3 is a very chunky sucker. It's equal to a Brux #4. No idea why....but I've been a Rock slut lately and they're getting harder to get.
In 6.5 CM, I wouldn't go any shorter than 22". And I personally wouldn't go any longer than 22"......LOL. But that's just me.
Or you could just do a Rem factory sporter contour.
McMillan Edge?? Or what do you have in mind for a stock??
Brux turned SS #2's in .243 and .264 for me, max length is about 23".