WHAT DOES SMOKELESS POWDER MEAN?

I could possibly get conversion cylinders for all of them in .45LC, however the 1858 can even be .38SPL as well as the 1851 .38LC. Since my rifle is .38SPL I'd personally ideally want the pistols to generally be in precisely the same cartridge, nonetheless I do not always want to obtain two 1858s and determined by my study I'm not precisely chompin