When I started fitting and chambering my self, I started with a small benchtop and had barrel between centers. I started a search that led me to buying a Nardini lathe with big enough hole in spindle to put barrel through headstock. I called almost every quality gunsmith in the country to inquire which was the most accurate method of chambering . There are many top smiths that chamber through headstock and strongly say it is the better method. Still I had not made up my mind until I visited one of the most noted smiths with many famous shooters on his customer list that I decided to go through headstock. If you do not have your machine trued( usually tailstock is out, and needs ground) then you can limit the runout by stretching out on bed, but it is still out. If you have your lathe trued, then your 60deg center that is centering your reamer is dead true-you dont have to allow for the runout with a floating reamer holder to let the back of the reamer to float. If you indicate your barrel in at the throat on the lands and grooves, the reamer is zero centered with the bore, which you cannot do out on the bed with steady rest that cant be indicated. Some even use steady reast with brass jaws that wear in minutes and need "readjusted" because there is no 60deg center keeping aligned when reaming. Either method will work, but I would suggest getting a big enough lathe to do through headstock if you so choose(you certainly can chamber with steady rest on bigger machine if you desire). I started chambering barrels 1.5" and wanted bigger hole through spindle. You probably think you wont do barrels that big, but I didnt either but I can do them when needed and still do sporter size and do feel the bigger machine is more rigid
