Years ago, I was gifted with one of these. Small pistol primers do well in it. LPP: not so much. It seems they hang up right at the hole that drops them down into the tube.
When this happens, I would remove the clear cover, unscrew the stabilizer plate, and clear the jam then reassemble—this took longer than loading the tubes one at a time. Some primer brands were worse than others. I found the machine had to be level to improve but not eliminate, the problem.
Just yesterday it did it again and being in the middle of a reloading cycle and a bit miffed I just shook the machine—one shake . . . and the jam cleared! Nothing spilled out, the machine continued to run and all the primers ended up in the tube.
While loading another box of 100 the jam happened once more, I shook it and again the problem was solved.
I’m not saying this is the best way to get the primers in the tube but so far it’s working for me