I think that it being related to the U.S.iconS. Atherton is implausible as well, I did to begin with after the first translation before posting on this forum. I can't think of a situation in which someone would engrave an Anglo-Saxon name on a rifle in Japaneseicon either though. Assuming that it was an engraver marking their work, which is at least the best theory we have so far, do we know why they would engrave their name in the barrel with fairly large katagana, when the barrel has otherwise not been engraved? It definitely isn't an aftermarket barrel, unless the WWI-era markings and rifling were being imitated. The markings on the magazine floor plate are tiny by comparison, even for the relatively small available space.