Primer cups coming off when decaping???

[mikenbarb]

Im having problems with some .357 primers not coming out in the decapping process. Just the cups are coming off and seperating from the rest of the primer leaving the sides of the primer still in the pocket. What the heck could cause this???? They were regular Federal nickle plated factory loads and were tumbled for 3 hours before I tried to decap and size them and now this happens. Its not all but about half of them that are doing it.

 

[Stargazer]

Perhaps a batch of very hard primers and the end cup is breaking off from the sides. They may use some sort of sealant as well which may be adding to the hesitation for the entire primer to let go. Just some thoughts.

 

[Sport45]

Are you sure the primer is separating? I don't remember what cartridge it was, but I once had some with a stepped primer pocket that looked for all the world like walls of the primer cup were left in. I measured the ID and found that wasn't the case. I did have to chamfer the step out to facilitate re-priming as it was difficult to start a primer against the square edge. Try seating a fired primer in the cup upside down (rounded end first) and see if it wil fit.

 

[Unclenick]

That's a new one on me, but since nickel plating is often associated with LE rounds (from back in the days of leather belt loops for revolver ammo), an unusual sealant may well be to blame. Still pretty odd, though.

I would take them and soak them for a week in Kroil or other penetrating oil, then try again. You could also try hitting the primer with a freeze spray, or setting the cases on a piece of dry ice to see if changing temperature that much cracks the bond? Heating them could have the same effect, but you don't want to get them hot enough to anneal because that will weaken the heads. I did that to some .45 ACP brass once. Not a good plan. Limit the heating to 300°F.

 

[mikenbarb]

I found that squishing the primers again with the good ol' 310 tool and a priming die loosens most of them up enough to get them out but still have a few hanging in there. I have never seen this before where the end of the cups are seperating off the rest of the primer. Im getting a disc like little frisbee. Heck of a way to explain it but thats what they look like. Theres no sealant on these and their just nickle coated Federal cases that are pretty new. Im going to call the factory tommorow and see if its been a problem. Possibly new primers their using or something like that.

 

[Unclenick]

If you are getting a disc like a Frisbee, then the primers are weak at the corners for some reason. I would let Federal know as that comes with the possibility of them giving out during firing. Normally, when a primer is hard to remove, as happens with some military crimps, the decapping pin stretches the primer cup to noticeably deform it disc. If it were to separate at that point, it would look more like a hollow base cone. Brittle primer cups. Odd.

 

[mikenbarb]

UncleNick, Their definatly looking like fiisbees and not cones. I will call them tommorow and see what they say.
Just an FYI, These are factory once fired rounds and not reloads and they let loose all at once with almost no stretch.