Ammo can be bought in a few places, but the cheapest is probably Grafs & Sons, once you factor in shipping. Expect to pay at least $1 per round. Reloaders may have a better time of it, as there are dies out there, and brass can be found at reasonable prices (again, grafs). Use the same bullets as Russian Mosins or .303 Brit. (.311 or so). Probably best to slug the barrel of any milsurp, especially a wartime one.
Elmer: They had (and have...and right wingers in Japan still use) lots of racist terms for all foreigners. Some of the worst are reserved for Koreans and Chinese, but westerners have a number assigned to them. Some are pretty subtle. Most aren't. And amusingly enough, some of the younger generation use them without any idea of just how insulting they can be...
Irwin: Most commonwealth types I've met have expressed similar feelings and ideas about the term when it came up in conversation. I'm pretty sure it's a matter of context. Most commonwealth countries didn't have Japanese internment camps during the war. The West coast of the US had a lot of Japanese immigrants and their kids (US citizens), and they were pretty successful in the fishing and farming industries. There are a lot of complicated nuances, but there was a lot of anti-Japanese resentment in some communities long before the war. A lot of farmers & fishermen benefited economically (to a great degree) when the camps started up and people had to sell pennies on the dollar, or made handshake deals that were never honored. People tended to use the terms interchangeably between enemy soldiers and Americans of the same ancestry. That's why the Japanese communities on the West coast, for the most part, feel the same way about those words that people of African or Hispanic descent feel about the more common racial slurs heard today. If your grandmother, or someone in your circle of friends and acquaintances had been held in a concentration camp, you might feel similarly. The UK never had those camps, so the term carries less punch there.