Why are my rounds not de-priming?

[DarrenL]

I thought this problem had gone away, but now it is back. Cases will simply not de-prime. Like 1 out of 3 cases

Dillon 650 using RCBS sizing die/decapping pin. Die is seated such that the shell plate just grazes the die when the handle is all the way down. Decapping pin is greater than 3/16” below the base of the die. The die has no spring, the pin is fixed in place with threads and a nut. There is nothing in the die, I took it apart, cleaned it, and put a new de-capping pin in it. There are no holes in the primers that remain in the case. There is no pattern to the cases that fail, although blazer seems to occur a little more than the others, but it happens with at least a half dozen case brands.

I was reading about primer pullback, where a primer gets stuck on the pin and gets pulled back into the pocket. Is that a real thing? Apparently you are supposed to file the pin at a 45 degree angle to prevent this. Could the pin be too far below the die? Could some other action on the press be interfering? I am not having any trouble belling or dropping powder. Any ideas? Thank you.

 

[Realtor MA]

Is the shell plate a little too loose?

 

[TrashcanDan]

I was reading about primer pullback, where a primer gets stuck on the pin and gets pulled back into the pocket. Is that a real thing?

I've only seen that happen when the pin pierces the primer cup.

Is the shell plate a little too loose?

I'm betting on that.
If the die or the pin doesn't move up and down in the toolhead, then theres flex or movement in the plate.
If the pins making contact, and the primers still aren't dropping, then there should be a massive distortion in the primer cup.

 

[paul73]

pin is greater than 3/16” below the base

make it like a 0.7" below the base. see if that helps. what caliber is that? rifle of handgun?

 

[DarrenL]

make it like a 0.7" below the base. see if that helps. what caliber is that? rifle of handgun?

9mm

 

[Jay77]

Is this range scrap brass that could have sat out in the rain for a while?

 

[eboos]

Primers getting pulled back in by the pin? Dillon die supposedly solves this problem by the pin being sprung and flings the primer off.

 

[gerrycaruso]

Yes. Primers can get stuck on the pin and reseated. Dillon dies do solve that problem but RCBS do not.

 

[DarrenL]

Is this range scrap brass that could have sat out in the rain for a while?

Yes

 

[Broc]

Stick the pin out more.
Make sure it is tight and not getting pushed up by the cases.

 

[shootymacshootface]

I was getting a lot of primer pullback on my 550 with my "conventional" 9mm size/decap dies. Problem was completely solved by switching to a Dillon sizing die with a spring loaded decaping pin.

 

[RKG]

In the last few years I have decapped several thousand 9mm range pickup cases, using the RCBS Decapping die in a single stage press. This includes cases in which the primers were crimped. I have never had one single primer fail to pop out. So it seems to me that whatever is the problem has to do with the Dillon setup.