I had a couple of issues with my primer seater when I first got started, but a few minutes of deductive reasoning and fine tuning got it fixed just fine.
Things I would recommend:
1. Polish the groove your seater slides in and out of.
2. Polish the under side of your primer seater (the part with the wheel)
3. Use some graphite powder (or use a pencil and color all over both parts) to provide dry lubrication that won't gum anything up
4. My LnL AP does not have any sort of clip on the primer drop tubes - the drop tubes have a shoulder machined into one side that sits in the reciever that is bolted to the press. Unfortunately these should have been threaded, because inertia with a tube full of primers will eventually unseat the drop tube. I ordered a couple of the recievers that bolt to the press and JB welded the drop tubes into them. Have not had so much as a hint of problems out of my priming system since then.
5. Keep a long handled paint brush (one of those small fine ones that is about 1/4" wide) and every time you need to refill the primer tube, brush down the press and the primer seater. It takes about a minute and will save you a lot of time. About every 300 rounds, check the allen screw that holds the shell plate in and make sure it is tight. Sometimes it will loosen up just a smidge and can throw the shell plate off. About every 1000 rounds, I typically take the shell plate off and clean everything with the brush real good.
Like any other machine (yes, even Dillons) it takes some learning on how it operates and training yourself on the mechanics with a progressive.