I don't know the answer, but it's much more than I expected.
The primer in the attachment pic got caught between the primer transfer bar, and the case feed plate mounting.
Normally, it would be obvious. But this one was a little different. It was the last primer in the stack, and for some reason it didn't feed correctly (not normally an issue), and must have ended up on the transfer bar.
I loaded more primers and started having trouble seating primers. So I pulled everything off the press - found the last case missing a primer. Look around - no primer to be seen. Odd, thought it was getting the very last one. Figured I must have screwed up. Try to seat a primer. No luck. Look around some more, nothing. Pulle off the shell plate, nothing. This was the start of a new box of primers, so compare primers, they look the same. Check case pockets, same depth. Same diameter. Chamfer the case pocket, same result. Check the primer push pin - it appears to be pushing up high enough (that last 0.030" isn't obvious). Look for debris, do a little cleaning, exercise the primer a couple times, nothing obvious.
I guess I didn't learn from Einstein about expecting different results, because I tried half a dozen cases before I gave that up.
Time for a full inspection, disassembly, whatever. Grab one of those little high power flashlights to start looking for things to maybe take off under the shellplate, and lo, there's a primer stuck to the bottom of the shell feed mount. Pop it loose, and discovered it was stuck into a flat head socket screw.
That little bump on the left is where it had extruded into the socket head, and it wasn't planning to drop off anytime soon. And it was just enough to keep a primer from fully seating. Little guy took a beating and never once complained about it.
The primer in the attachment pic got caught between the primer transfer bar, and the case feed plate mounting.
Normally, it would be obvious. But this one was a little different. It was the last primer in the stack, and for some reason it didn't feed correctly (not normally an issue), and must have ended up on the transfer bar.
I loaded more primers and started having trouble seating primers. So I pulled everything off the press - found the last case missing a primer. Look around - no primer to be seen. Odd, thought it was getting the very last one. Figured I must have screwed up. Try to seat a primer. No luck. Look around some more, nothing. Pulle off the shell plate, nothing. This was the start of a new box of primers, so compare primers, they look the same. Check case pockets, same depth. Same diameter. Chamfer the case pocket, same result. Check the primer push pin - it appears to be pushing up high enough (that last 0.030" isn't obvious). Look for debris, do a little cleaning, exercise the primer a couple times, nothing obvious.
I guess I didn't learn from Einstein about expecting different results, because I tried half a dozen cases before I gave that up.
Time for a full inspection, disassembly, whatever. Grab one of those little high power flashlights to start looking for things to maybe take off under the shellplate, and lo, there's a primer stuck to the bottom of the shell feed mount. Pop it loose, and discovered it was stuck into a flat head socket screw.
That little bump on the left is where it had extruded into the socket head, and it wasn't planning to drop off anytime soon. And it was just enough to keep a primer from fully seating. Little guy took a beating and never once complained about it.
