Dillon Primer Seating Mystery Solved

[Mikul]

I began to suddenly experience problems seating primers on my Dillon 550b. The press would crush a corner of the primer. It happened with every type of brass except for Federal and PMC. I later discovered that if I pulled the brass to the left, they would all seat correctly.

So I called Dillon. They suggested that I check the shell plate for burrs and make sure that the primer cup is aligned properly. I did, but the problem was still there.

Soon after the shell plate failed to turn, so I took it off, cleaned it and put it back on. Suddenly, all of the primers were going in and it required almost no effort, but the powder funnel was crush the cases.

As it turns out, I had the shell plate too tight (exactly the opposite of what I thought the problem was). When it was looser, the brass could float easier and so the primer cup would self-align. I tightened the plate down to the point that it no longer crushes brass and no I can even reload NATO brass, which was impossible before.

Hopefully, my battle with the forces of physics can help others.