I have a wonderful Doug Turnbull 1886, takedown, half round, short rifle with 24"barrel chambered in 50-110 Winchester. I have shot 1.5 Swiss 100 gr. with a 300 grain cast boolit and it shoots great. I like Blackhorn 209 in some other cartridges so I called Western and asked the guy on the phone how much Blackhorn that I should use with a 300 grain cast boolit [20:1 metal]. He said to fill the case to the bottom of the boolit and use magnum primers. Then I asked and if I wanted to use a gas checked 435 grain cast boolit how much should I reduce my powder charge? He said that I can only use a 300 grain boolit....end of conversation. I asked why and he said that the 300 grain one was the only one that could be used. There is a 50-100-450 what then? Ideas or suggestions, please. Dr.C