I wish I did know an actual Japaneseicon person. Unfortunately, I do not.

I had been thinking about the same thing, Patrick Chadwick. why the underside of the barrel and inside the magazine floorplate to begin with? If you look at the entire album, it even looks like the magazine floorplate is Winchester-made, while the Receiver (and probably barrel) are Remington, yet they have identical characters, seems odd that they would bother matching up the magazine floorplate to a receiver that's already mismatched. Reading from top to bottom had been guessed by me, and further suggested by those who know Japanese kanji/katagana/etc, before I started this thread.

All of my responses on this specific thread were made before you identified the characters as Katagana and not Kanji, in the Japanese thread. I honestly do not know the first thing about traditional Japanese characters, and assumed that all were called Kanji. Do we really know for sure that Japan was using .30-06 Arisakas? The only thing I can turn up about Arisakas being converted to .30-06 was for use in Thailand, and absolutely nothing about Japan using the M1917 at all outside of captured rifles used by Japanese police when they took the Philippines. A U.S. coastguard vessel was sent to Greenland, which dropped off 50 M1917 rifles for its inhabitants to use to defend against the Germans once Denmarkicon fell against the Third Reich during WWII. For some reason we have plenty of information about these 50 rifles, and how they were put to use, but absolutely nothing at all about post-war use of the M1917 by the Japanese, as these Katagana may suggest. Maybe, assuming that this is the case, the Japanese have records of this having taken place, which have simply not been translated into English and/or are hidden away in some dusty filing cabinet somewhere in Japan. In that case, you would think there would be an appreciable number of similar rifles as well, and I can't seem to find a trace of any others like this one yet.

I have, thus far, been told by two different people, including Eaglelord17's acquaintance , that the Katagana translate to Atherton, but assuming that this is 100% accurate, the question of why the Japanese would engrave the name of a U.S. navy vessel into its rifles when the vessel will not even be called this while in service with the Japanese navy. I do believe that you're 100% spot-on about it being Katagana, as I found literally every single character other than the vertical line in the center in a Katagana alphabet table.

The more questions that are answered, the more pop up with this thing. I'm beginning to think this is going to remain a mystery unless someone who just so happened to be a former Japanese Navy armorer aboard a former U.S. Navy ship, somehow happens to see this and recognize it, which still assumes that this is actually related to why these Katagana were engraved on the rifle/s.