I recently re-discovered a bag full or cartridges I purchased at SLICS way back in 1999. Closer inspection of a severely corroded 450 Nitro revealed that it was, in fact, a 475.
I can’t get the headstamp to show up in a photo, and I don’t want to steal pictures from another website, but if you look at http://www.cartridgecollector.net/475-nitro-express-3-%C2%BC, it is the first headstamp shown, and the projectile is the one at the far left in the bottom photo.
I’m curious who actually manufactured the round, and about the bullet – which seems to be a departure from what one normally finds in British nitro express cartridges.
Incidentally, the bullet pulled right out due to a cracked neck, and it was loaded with ribbon-like cordite (axite?).
Any insight would be appreciated.