Source Found for Caps (in the US)

Well I bit the bullet and found some MGC 7mm caps being sold on ebay. I'm in the US and the seller is in Japan. I went ahead and ordered. I received them in hand in 5 days. They were shipped via Fed-Ex.
Look on ebay under seller "biwachannel_shop", this is who I bought them from.
I really expected my purchase to fall apart because they had to be sent to the US, but I have 5 brand new boxes of MGC 7mm caps in hand. Will probably use one up in the next day or two, since its been a real long time since my MP40 ran.
The ebay seller also has MCG 5mm and Marushin 5mm & 7mm caps.
Limited supply of course, but good luck to those who see this in time before the guy runs out of stock.