Deadeye 47
Reaming a rifle chamber is usually done by a qualified gun smith. So like many shooters it is not surprising that you don't know the make up of a chamber reamer, no big deal.
The big deal is that a chamber should be concentric with the bore. very few barrels are really straight, because it is nearly imposible to drill a perfectly straight hole. Top of the line match barrels come close. Cheap barrels are straightened inducing stress. These barrels will wander when they warm up during shooting.
When a barrel is not straight and you want a concentric chamber, you need to dial in the part just ahead of the chamber with a dial gage, which requires to use of a deltronic indicater. with this devise you will know that the first part of the bore is in line with chamber. Even though the barrel has a slight bend. or a run out.
The pilot on the reamer will be land diameter less 0.0002 at that place and will guide the reamer concentric into the bore.
Some rifle barrels have a 2/10000 or more choke. So a pilot that fits the bore at the muzle could be too big for the chamber end.
Doing a chamber by hand with a brace will do a pretty good job so long you have a good fitting pilot on your reamer. Just make sure no chips get near the pilot, clean often and go slow with lots cutting lube. Some barrel steel will not work with a reamer turnrd at hand speed.
Lath speed can be anything from 60 -240 RPM depending on the steel.
Eh man, I have never chambered a rifle, so don't take my bit of bable for ghospel. I always let my smith do it. Though I own quite a few custom wildcat reamers.
Good luck with your new chamber.
Fred M