Electromachining has it's place, for the low end home gamer but not the best option for high end production barrels.
Electropolishing, if that is, in fact, what they were using, is not electromachining, per se'.
Electropolishing is intended for burr removal & rounding of sharp edges. It is done in a concentrated sulfuric acid + concentrated phosphoric acid bath using the part to be "polished" as an anode with inert or lead cathodes.
It produces a very highly polished, very low surface finish depending on the exact SS alloy.
It is very difficult to ensure perfect current density distribution (i.e., stock removal) over the entire surface being affected, especially at the ends as the effective current density applied to an electrode is always higher at its ends that in the middle; the amp meter can only measure & adjust the average total current, not the uniformity of its distribution.
If that makes any sense to you......................
MM
