Now it may be harder to ignight {sp} replica black powder but I sure would not like to take the chance of a possible chain fire which is one of the reasons of using Crisco or other types of grease over the loaded chamber as well as making the powder residue softer to make cleaning easier, but the only other alternative would be the use of lubricated wads between the powder charge & ball.
You may want to give the lubricated wads a try like the ones from
http://www.bpstuffllc.com/ they are quite resonable in price & seem to work quite nicely.