Tinker - I only have four or five of the bullets, just some samples I was given. The mould is in the case with a pristine Royal, cased with every conceivable accessory, which sadly I do not own. A close friend was a previous owner of this gun, and he said it shot perfectly with these bullets.

I do, however, have a cherry I have made to duplicate the bullet. It should drop them in the low .670's (I've yet to cut a mould with it).

BTW In his book on the Paradoxes, Roger notes the 16 bore load was 2 1/2 drams with a 625 grain
bullet.
The bullets I have here are lighter than that. There seems to be quite a bit of variation, I have
observed original 12 bore H&H moulds throw solid bullets anywhere from 725 to over 800 grains.