My .500 3" BPE nitro-for-black load clocks at 2040 fps with the 335 Ranier bullet.
The standard black powder load in this cartridge was 4 1/2 drams (123 grains) of Curtis & Harvey's #6 behind a 340 grain bullet.
Here's a view of my Purdey:
http://rbsiii.com/collection/rifles/purdey_500bpe/
We are straying away from the subject of this thread.
Curl