Drew I can not speak for what others are thinking, though if the Brazing rod used was a Copper/Silver or Copper/Nickel Alloy I could see no problem in using it for joining steel/Iron. But to repair a gun barrel like that it is sort of buying your self a ticket to oblivion or a hospital emergency room from a roulette table. And if you want to use a brass stop that is also fine though I would decline its use in a gun of mine.

The only lessons in my life I truly did learn from where the ones I paid for!