Get the floating pilot reamer for sure.
But also. . .
. . .consider getting a set of pilots for that particular caliber as not all bore dimensions are equal.
David sells em for about $8.00 each and they come in .0002" increments.
I have complete sets for every caliber from 17 to 40.
While I completely understand where Cowboy is coming from with regards to the importance of ammunition preparation and the effort to wring out every last little bit of accuracy from a particular set up, I must disagree for one (potential) reason.
IF (notice the IF) this rifle you are building is a field/working gun then I think its a bad idea to make it require specialized ammunition.
What if the luggage is lost? Now you can't just buy a box of ammo, you need a whole reloading room.
What happens to those thin walled necks ability to tolerate the recoil when they are stacked up in a magazine? Now your seating depths potentially change every time you pull the trigger.
Minimum tolerance chambers are great on the firing line at the range or at a match, but if your out in the world clawing your way up a hillside or out in open terrain with 30mph winds blowing, crap is going to get inside that gun and it will fail right when you need it most. If this were not the case I'd of seen designated marksmen carrying fireformed, neck turned, custom loaded ammunition for bench rest chambered rifles during my three year tenure in Iraq. (never saw that once)
If the old Marine Corps M-40 in 308 can kill a man with Lake City 175 grain bullets (cranked out by the gajillions) out to 1,000 yards I would hope that a 7mm WSM
can successfully harvest game anywhere in North America.
This is in no way meant as a confrontational dialog. Just difference in opinion.
Cheers and all the best,