First thing I do on any new rifle is check the chamber's neck diameter and write it down. Then I'd say a chamber cast,but I skip this and go straight to finding jam length on the bullet I intend to start with,and write that down. Somewhere on the top of this rig's load book(each rifle here gets it's own book because if the rifle goes down the rd,it's data needs to go with it)is going to also be what the fired neck diameter is. Then,need to know how the FL die,screwed all the way down measures up to the chamber(this is what the chamber cast should bare out).... on a Savage,I'm not the least bit opposed to resetting the headspace based on my FL die. Can do the same with my R700's but is too involved to go into.
If the bullet and twist rate are happy together,which should've already been decided on..... Then,and this also was already thought about,I'll have about 3 powders that are gonna be tested. And pretty much know beforehand what it's gonna like but,you never really know until you try. Same with primers,got my favorites but you owe it,to at least test a cpl others.
Fire form with an eye on not only the cases but will clean during this period. Not from a break in standpoint,although it does slow down the pace so overall,cleaning a bit extra at this time isn't hurting. Nope,cleaning is to learn how easy this barrel is going to be down the rd. I use JB and Remington 10X on factory barrels during this stage. Just trying to get a handle on the barrel. One other thing about early,thorough cleaning is,as a hunter,I have to know what this rig can do coming off a "deep clean". You never know when it may pop up,how many fouling shots does this barrel need to get back into the X? Keeping round count early on helps in this aspect as well.
There's much more to it but that's a decent start. You need to fire form anyway,so take that time to check some things and write it down.