Tonight I loaded a few hundred rounds in my 550B with new Starline Brass.
As I was seating the primers, I noticed that some of them were flattening out and showing some primer denting. At the same time, I also felt some resistance and saw some "chattering" of the primer pickup bar. I had about 8-10 primers left in the tube at that point. Needless to say, I took the primer assembly apart, cleaned everything, and reloaded a new tube full of fresh 150's. It seems to be ok now.
Does anyone know what the problem was? The primer looked ok on the cup before seating. Do you think I may have seated them too deep? I do have my shellplate fairly tight and normally seat my primers at .004"
I do like the feel of the Fed's when priming as they give good feedback when seating. The WLP's I had been using previously, were giving no feedback or "feel".
Thanks,
Hawker