Don: When using these "light" loads in our brass framed guns, pour a little Cream of Wheat, flour, Corn Meal, so similar powder in on top of the powder charge until it is about 1/8 inch below the mouth of the chamber. Then ram the ball down so that it is slightly below the front of the cylinder.
Most folks have found that having the powder compressed and the ball at the chambers mouth (instead of rammed way down into the chamber) gives the best accuracy.