Primer pullback?!

Luciano · July 12, 2012, 01:58 PM

So I got my first mystery decapping problem yesterday with some F.C. 9mm brass. No matter how I'd adjust the decapping pin the spent primer would still be in the pocket. Luckily I noticed the problem right away as my case feeder would not feed another shell, it moves the shell into place at the end of the upstroke. Loading on a Dillon 650 with RCBS dies. A quick search today revealed the culprit. I tapered the decapping pin and loaded the FC brass with no problems. Have you had that happen on other calibers too?

Stressfire · July 12, 2012, 02:11 PM

Was decapping and sizing a few FC 9mms last night and had a few not want to go into the die (using RCBS as well) - looked as though the lip of the case mouth was catching just enough on the edge of the die to hang it up. Was a bit weird, a touch with my finger corrected it - glad I didn't try to force it in.

Not to come off as a complete rube, but what do you mean by "tapered the decapping pin?" Still trying to wrap my head around terminology

SL1 · July 12, 2012, 04:21 PM

I think he is saying that the spent primer was pushed out of the primer pocket by the decapping pin, but then pulled slightly back into the pocket by sticking to the pin as the pin ws withdrawn back through the flash hole. That leaves the primer almost out of the case, as if the decapping pin had not been adjusted quite far enough out. However, adjusting the pin doesn't solve that problem. Lightly sanding the pin to a slight taper, so that the primer anvil will not grab it, does solve the problem.

Right?

SL1

Brian Pfleuger · July 12, 2012, 04:49 PM

That's how I see it.

I think there's a few dies with spring loaded pins too. Seems like a complicated solution to a simple problem.

**Unclenick** · July 12, 2012, 04:58 PM

I agree that's it. I've seen the phenomenon, too. I think it may depend on the anvil design as much as the decapping pin, as the problem tends to predominantly occur in association with a particular headstamp. CCI, for example, makes it's military hardness primers identical to its regular magnum primers except the anvil is differently shaped to reduce sensitivity. (Not that I've had any issue like this with CCI, but rather it's just an example of anvils not being identical, even within one brand.) I used to keep a small broken drill bit sticking in the end of a short length of 1/4" dowel for poking out the occasional primer that did this. Now I'm wondering what I did with it. I haven't needed it for awhile.

Luciano · July 13, 2012, 12:20 AM

SL1 got it right. I polished the tip of the decapping pin until I got a slight taper.

The spent primers were getting fully seated back into the case. That left me puzzled to say the least.

Stressfire · July 13, 2012, 01:57 PM

Quote:

I think he is saying that the spent primer was pushed out of the primer pocket by the decapping pin,

Aaaah, I gotcha

serf 'rett · July 13, 2012, 02:48 PM

Get primer pullback all the time when decapping on my drill press with a nail.

I decap before wet tumbling with sst pins.

PA-Joe · July 15, 2012, 06:15 AM

Try polishing the pins. I recall some of the pins being very rough.

July 12, 2012, 01:58 PM	#1
Luciano Senior Member Join Date: March 22, 2006 Posts: 111	Primer pullback?! So I got my first mystery decapping problem yesterday with some F.C. 9mm brass. No matter how I'd adjust the decapping pin the spent primer would still be in the pocket. Luckily I noticed the problem right away as my case feeder would not feed another shell, it moves the shell into place at the end of the upstroke. Loading on a Dillon 650 with RCBS dies. A quick search today revealed the culprit. I tapered the decapping pin and loaded the FC brass with no problems. Have you had that happen on other calibers too?

July 12, 2012, 02:11 PM	#2
Stressfire Senior Member Join Date: June 16, 2011 Location: Ohio Posts: 1,497	Was decapping and sizing a few FC 9mms last night and had a few not want to go into the die (using RCBS as well) - looked as though the lip of the case mouth was catching just enough on the edge of the die to hang it up. Was a bit weird, a touch with my finger corrected it - glad I didn't try to force it in. Not to come off as a complete rube, but what do you mean by "tapered the decapping pin?" Still trying to wrap my head around terminology __________________ "The best diplomat I know is a fully charged phaser bank" - Montgomery Scott

July 12, 2012, 04:58 PM	#5
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	I agree that's it. I've seen the phenomenon, too. I think it may depend on the anvil design as much as the decapping pin, as the problem tends to predominantly occur in association with a particular headstamp. CCI, for example, makes it's military hardness primers identical to its regular magnum primers except the anvil is differently shaped to reduce sensitivity. (Not that I've had any issue like this with CCI, but rather it's just an example of anvils not being identical, even within one brand.) I used to keep a small broken drill bit sticking in the end of a short length of 1/4" dowel for poking out the occasional primer that did this. Now I'm wondering what I did with it. I haven't needed it for awhile. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

July 13, 2012, 02:48 PM	#8
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	Get primer pullback all the time when decapping on my drill press with a nail. I decap before wet tumbling with sst pins. __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

July 12, 2012, 04:21 PM	#3
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	I think he is saying that the spent primer was pushed out of the primer pocket by the decapping pin, but then pulled slightly back into the pocket by sticking to the pin as the pin ws withdrawn back through the flash hole. That leaves the primer almost out of the case, as if the decapping pin had not been adjusted quite far enough out. However, adjusting the pin doesn't solve that problem. Lightly sanding the pin to a slight taper, so that the primer anvil will not grab it, does solve the problem. Right? SL1

July 12, 2012, 04:49 PM	#4
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	That's how I see it. I think there's a few dies with spring loaded pins too. Seems like a complicated solution to a simple problem.

July 13, 2012, 12:20 AM	#6
Luciano Senior Member Join Date: March 22, 2006 Posts: 111	SL1 got it right. I polished the tip of the decapping pin until I got a slight taper. The spent primers were getting fully seated back into the case. That left me puzzled to say the least.

July 15, 2012, 06:15 AM	#9
PA-Joe Senior Member Join Date: June 9, 2010 Location: NEPA Posts: 909	Try polishing the pins. I recall some of the pins being very rough.