I also found I needed to tap the funnel on the inside of the barrel to make sure all the powder is out of the measure
I to have a brass measure with the spout. The way I avoid the above problem, especially when using a coarser grain like 2F, is to do the following:
I bend my thumb over the edge of the measure where the two parts come together.Leaving my thumb in this position, invert your hand and tip the spout in to the barrel as normal. When you feel that you need to tap the measure, instead of tapping the spout against the inside of the barrel, I move the measure up and down about an inch or so and let my thumb act as a cushion between the barrel and the measure. (don't tap hard!)
With your thumb in this position on the measure, it also acts as a hold to keep the spout and the measure aligned properly. Not something that has been a problem, but better safe than an embarassing mess.
JM2C
~Robert