The genius in this set-up which is very old is that a .22lr case will for most people hold exactly 3 grs of Bullseye.
Bullseye is very fluid and fine, the case is the right shape: IE; deep and narrow to measure this type of powder. Most powder measures, even those designed for small volumes of pistol powder, do not have the best shape for these small amounts, I have never tried to throw the 1gr charges that Dick used, but I suspect my Redding would not do it well.
When I ran across this tool I started throwing to a pan on my Acu-Lab and I started hitting 3.0+/-.03 in about 10 throws.
In that era I was not in the least interested in changing bullets or trying different powders what worked was more than good enough 3.0grs was the 38 spl load then.
Lee is a Johnny come lately to the dipper business, a dipper or cup on the end of your powder horn was it for black powder

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