Dear Mr agent00 - FYI 2.5 drams = 68.5gr.
There are a great many books on British percussion arms. Sadly, many of them are a mite esoteric and therefore not to be found in the bargain bucket stores - figure on $100 to $200 a pop. You will have to rely on Mr Minshall or our mutual friend, Mr Bill Curtis [of Curtis and Harvey black powder fame]. He is THE definitive British expert on weapons of the Crimean war and that time. He can be found at the Royal Armouries in Leeds, UK, but I regret that I do not have his e-mail address.
tac