When loading black powder cartridges I do not use a normal powder measure but rather the Lyman Black Powder Measure. People still argue about whether or not a spark is possible with the regular measure, which would ignite the black powder. I prefer to err on the side of caution and use only a powder measure designed for black powder use. When using percussion pistols I never load directly from the flask into the cylinder. The reason being there could be a spark lurking in the dark confines ready to give a very dangerous ka-boom.

Instead, the powder is first poured into a hand powder measure, and then only this one load is placed anywhere near the cylinder. I keep several brass flasks with a measuring spout for a particular amount of powder and then this is easily transferred into a hand powder measure. Or I use an adjustable hand powder measure to come up with the proper charge.