For some ideas what one man did to get his Dickson shooting look at this link (scroll down to CptCurl May/14/2017):
I don't know if the photos will come up for you but in the one of the Eley 1893 Catalog note that the Nitro for Black powder charge (BP 142 grains - SP 54 grains) for the 440/480 grain bullet is a little under 40% of the BP charge which fits in with the oft quoted 40% using 4198 (is it?). Also note that his in in the 3 1/4 inch version.

Last edited by HalfaDouble; 08/18/19 06:01 PM.