I normally wouldn't post on a subject like this, but I've had it with the misinformation and disinformation on this board, much of it peddled by proponent(s) of "torch coloring" shotgun frames. To start with, the vast majority of prewar guns' frames are made of 1018 or 1020 steel. This is a mild steel with a low carbon content that is NOT hardenable, meaning it can be heated to any temperature no matter how high and quenched and it will not harden. It lacks the carbon content to do so. This is the reason for case hardening. There is no tempering necessary after case hardening in mild steel as the core of the material remains unchanged. Only the surface is hardened to a depth of between .002 and .005". All this talk of drawing and tempering only applies to "through-hardening" steels. No prewar American made shotgun ever used a through-hardening steel in the manufacture of it's frame. I know this because I have the factory drawings for most maker's guns. The material is called out for each part on the drawing. The only thing that torch coloring accomplishes is localized annealing of the remaining case hardened skin on the frame. I contend that this practice is more dangerous than proper case hardening. Before one makes proclamations about metallurgy and what the factories did, they should do some research. Otherwise keep your hazardous opinions to yourself.
Thanks Dewey, the facts period.........AMEN....!!..........
