Mark, and all:
The hulls are Remington Gun Club, and after de-priming them, if you set them on a flat surface they wobble ever so slightly. Not much....but enough to notice.

Sounds like they're bowed and if so something caused it - maybe too much head space in the gun they were fired in. Just a guess. Or, what were they deprimed with ? My Mec 9000 will bow the shell. With a Grabber or 9000, if the shell doesn't drop all the way down in the deprime station they will do that.

I load 20 ga STS with Win. primers. No problem at all through 10's of thousands.

A friend of mine had difficulty with Cheddite primers in his 16 ga loaded with Green Dot. He had frequent bloopers, especially in cold weather. Switched to Win primers and the problem went away.

Gary, think we got off track with different primers. Austin said primer pockets were big and the bottom of shells were not flat. I don't know if the press caused the bottom to bow like my 9000 will. The shells rock in the press and will fall over when it happens. And I don't know if that will also enlarge the primer pocket. I would first check the shell before and after it was deprimed for flatness. I would also deprime by hand [ a dowel and nail ] to check the primer pocket. See if it stayed tight when done by hand and when done with the press. Also, do you have this problem with other brands of shells ? Just some suggestions to start in the beginning.

Yes, these threads tend to evolve into something other than originally intended. I am guilty of contributing to it. Sorry, but the discussion was still interesting.

Anything that puts a lot of pressure on the hull can cause the brass to bend or dish. Way the problem sounds and without looking at it, if dished the primer seating stem is probably too high. Or if the hull is bowed out Primer punch could be responsible, running too deep punch the primer and going to far.

I get suspicious if the press takes too much effort to operate, lot of leverage you can push hard, but should not have to.

William

Never notice it with a 9000H. It has about 650#'s of pressure and if the shell doesn't drop down to the bottom of the collet it'll bow the base of the shell. It's happened more than once.

Thanks for the feedback so far, but the pierced primers are what had me believing that the problem may have been high pressure.

It's possible, but of my 10 different SxS's, only my Parker hammer gun will pierce a primer with the right barrel. I should check it against the other firing pin for sharpness/length.