Steve,
When I used to build m/l rifles I used it. It worked fine for me. I just heated a large old coffeepot or kettle full of water to boiling, poured it down the barrel as it stood upright in a bucket. This heated the barrels to nearly the temp of boiling water, probably close to 200 degrees. Worked fine for me. I tried a second application of boiling water to a barrel one day, in order to reapply the solution. When I hit it with the boiling water the second time it turned a very nice blue/black ............... not what I wanted!
SRH
