I use the Knight combination brass flask and powder measure. You fill the brass powder flask then stick the measure in the bottom, push the slide and give a few shakes, shut the slide and you're done. No muss, no fuss. Here's a link to the description on Knight's website. I picked it up on sale at a local outdoor store.
http://www.knightrifles.com/productD...aspx?id=324306
Traditions has a similar item, here it is a Wholesale Hunter:
http://www.wholesalehunter.com/produ...productid=5423