When ready to shape the barrel band close to final dimensions I normally use and endmill to rough out the contour to match the barrel. The majority of the shaping is done on a belt sander, rounding all the contours so they are down to the final contour and dimensions. Radius the corner where the sling swivel is mounted so that the swivel can swing 90 degrees in use. The rest is hand polishing.
If using the standard button magazine tube place the band so that its forward edge will be just behind the screw that retains the magazine plug. Often clients ask for full-length magazine tubes when making this conversion, the barrel band must be mounted behind the front sight, so keep that in mind. Be sure to trial fit the whole thing before you solder the band to the barrel, that will save you tearing it down to fix something, or reposition the band.
Soldering the barrel band in place, I use Hi-Force 44äSolder from Brownells. It is 96% tin and 4% Silver, it flows freely at 475° F. Much cooler than silver braze so no danger of damaging the bore of the barrel. I have yet to see a sight or band move that has been properly tinned with this solder.
Just clean up the solder and flux, prep the metal as desired and blue or finish as needed. Caustic bluing salts will eat this solder at about .001” per minute so minimize time in the bluing tank and be sure to neutralize the salts.
If you install a full-length magazine you will have to replace the magazine spring as the factory spring will be far too short. I also turn a new magazine follower out of Teflon rod to decrease the mass of the follower, which under recoil can pound on the ammo and contribute to the forces trying to drive the magazine off the rifle.
200 South Front Street
Montezuma, Iowa 50171
http://www.brownells.com (solder and flux)
PO Box 5
Adna, Washington, 98522
http://www.wisnersinc.com (magazine tubes)