Yikes! I have fired it numerous times without any adverse consequences and thought that since it was hammerless that modern powders were suitable. Is it because there is no reference to the word "Nitro" that makes it Bp? Did find some additional proof marks BV and NP if that is significant.

Also not sure i understand 6o-400 Max as can't see how that could relate to grains of cordite as would not 400, if grains,not fit any brass other than a small mortar?

Thanks so much and look to hearing more.