Through my use of the lee ppm I have found it leaked,and subsequently would bind. I cured this by lapping the rotor to the body. I disassembled it and put lapping paste on the interface between the rotor and body. I put the screw back in the rotor and used my cordless drill to spin it in the body. I cleaned it and reapplied graphite to the parts everywhere inside. It completely cured the binding but I still had some kernels of powder here and there.
There turns out to be a slight ledge on the end of the metering chamber. When the metering chamber is down, there is a slight backwards tilted edge. This holds a few kernels of powder. If you throw charges consistently, the same amount of powder hangs on that edge each time. But when you stop, a bump of the bench or the measure itself, dislodges those kernels and they go all over the bench. Thus appearing as leakage. That small amount of powder equalled .2 when I would tap the measure to dislodge it into my scale pan. Not acceptable to me.
I thought it through and figured a way to address that issue as well.
I removed the drop tube assembly so I could inspect the metering chambers end. I removed the sharp edge with a sharp knife, only on the part that was in question, not all the way around the edge as the upper part is where the powder is struck.
Removing the sharp edge on the metering chamber moved the edge back far enough powder would catch on the edge of the hole in the body. I then moved that edge farther back, so that it wouldn't catch powder. Checking through the hole where the drop tube was, I removed material from the edge of the body hole with te tip of a pocket knife blade. I was able to move it far enough back so the powder would flow past instead of catching on a lip. It isn't completely straight down but at a slight angle.
Then I sanded the areas I trimmed with fine sandpaper, blew it off, and wiped off dust, and then applied a coat of graphite.
Now I have very little kernels that hang up. There still is some but maybe .05 to .1 worth at most and often none. Likely a difference in the way I knock at the bottom of the stroke. I try to do the same but other than a hard knock, it's difficult to be 100% consistent here.
I have done two PPMs this way, the first I wasn't as aggressive on and it has the more variance between the two. I plan to give it another once over.
Overall I'm quite satisfied with the results. My measure are more user friendly and more accurate.
