Did a search and here is what I found:
"the recommendations on the primers to use due to a legal issue that they had to deal with. From what I had been told, it involves what happens from the way "some" of primers are made. In a nutshell, primer compound dust built up in the flipper tray ridges that Lee uses to hold the primers, and a static electrical discharge ignited the build up of priming compound dust and then ignited the primers in the tray of the tool. One can only imagine what happened from there from a legal view! It is because of this incident that Lee makes the recommendations that they do. However, I did read several years ago,from a member of the Cast Bullet Association, how one can alleviate this situation of the build up of the primer compound dust with the Lee tool, as well as any of the primer flipper trays that are available to the reloaders. From time to time you should wash these trays in dish washing detergent and let the suds dry on the tray. This knocks the static electricity charge down and prevents an accidental ignition of any build up of priming dust. I would imagine that you could use an anti-static spray for this purpose as well, but I will still wash my trays in detergent since I know that the tray is clean, and safe."
I am told that Federal primers are a frequent culprit, but I do not know why this should be. I just don't feel good about using the Lee Autoprime with that explosive potential in front of me.
