Why do you want a rail "brazed" (actually it is not Brazed but a form of silver soldered or oven welded) to the barrel? Why not drill and tap the barrel and mount a weaver style rail that way? I have done this to NEF and Rossi and it works great at a fraction of the cost of having someone mount a rail for you. The last one I checked on having a cantilever rail "welded" to the barrel was over $200 as it is all hand fitted.
CPL holder since 1991, NRA Lifetime Member, DU Member, NICET certified
"For those who would give up essential liberty to purchase a little temporary safety, deserve neither Liberty nor safety.—Ben Franklin.”