I believe the case label says 70 grains of Cordite, the handwriting in Victorian times is often very hard to read. Holland & Holland had promoted the 500-450 bpe before the advent of Cordite, when all of the British makers were trying roll out new smokeless offerings the 500-450 was Holland's standard big bore offering until the .465 was developed. There was nothing special about the 500-450 cartridge case, just marketing. Advertising of the day stated that both the 480 gr loading and the 365 gr loading printed to the same spot(out to 100 yards). The standard 365 grain load carried 70 grains of cordite while NFB loadings varied between 52 and 63 grains of cordite behind a 365 grain bullet.
Thanks and you are right. Look at the "4" in the rifle number on the label. Should have seen it earlier.
