Alright, it took some time but it was worth it. My reloading equipment is in my detached ?single? (in 1940?s) car garage or I should say sub-compact in today?s standard. The test was done in three separate session. The auto drum setting was not touched since the last time I used the equipment.
But before here is my just finished powder cabinet. It is nice to have a proper place to store my powder. I can fit 29 Hodgdon style 1 lb. bottles in the top shelf. I know that it may not take too long when I will have the need to find more space
Here is my reloading bench. I followed the steps listed in my last post with the suggestion from Wobbly. The powder used (in order) for the test were: VV N320, Hodgdon Universal, and Accurate #7.
All the powders loaded fine with the auto drum. There were no leakage noticed on the press area. When switching to a different powder, the content were emptied back to the container; the hopper and the neck area where cleaned from any residue with compressed air.
However after switching to the last powder, I noticed in the first sample three flakes of Universal flakes among with AA#7?s powder. I turned off and removed the hopper. The neck area were emptied and noticed two Universal flakes stuck in between the wiper and the drum. The drum was removed for further inspection.
Here are some stuck Universal on the wiper along with some AA#7. If I left it alone, eventually it will be loaded with AA#7 that in which will degrade its performance. Other than the powder stuck in the wiper, there were no powders residues in any other areas. I cleaned it and proceed to cycle the auto drum. The real source of these flakes were coming from some of the cases. It was noticed that the Universal has a little more clinging properties.
For to ease 1SOW ?s concerns, there were no even leakage issue with #7 after the test was completed. I proceed to slowly open the drum to see if there are any AA#7 powder stuck. As you can see there are some powder stuck in the wiper. There are some powder in the ?no leak grove? (page #9 in the instructions).
With the aid of gravity, the groove serves as a reservoir for loose grains of powders that find their way between the drum and the powder drop's body. This is why the cavity was machined as a conical cylinder instead of a traditional cylinder with O-ring commonly found in others rotary powder drop system. I also noticed a small port in the grove that leads to the powder drop tube. I believe as loose grains get collected in the ?no leak grove?, the movement of the drum will eventually push some of them into the drop tube. This action will prevent the ?no leak grove? from overfilling that can result in leaks.
Now here are the results from this test.
Based on the data collected I learned several things:
1. My Frankford Arsenal Platinum scale has tendency to drift to the lighter side despite that it reads ?0.0? when placing back the pan on the scale. Compared to the Lee beam scale, it tends to read in the lighter side. From now on, I will be using my Modified Lee Beam scale. Going back to my records, I was loading 9.1 grains of AA#7. Based on this test, I was short a tenth of a grain because I was using my Frankford Arsenal scale.
2. So for the purpose of data analysis, I am using the results from the Lee Beam scale. The powders that had almost the same standard deviation were the N320 and Universal. The AA#7 had the most variation of the standard deviation despite that has the same average.
3. To answer the question if a baffle is required when using the auto drum; I can say that it depends on the powder. Definietely it is needed for super fine ball powder like AA#7 or #5. I could do another testing if I will get the same result with a baffle installed. But for now it was an interesting test.