What is a "Cocked" primer?


December 7, 2010, 12:09 PM
I just received my new Lee Auto & Hand primer.

The instructions warn of possible primer explosions and cited a "Cocked Primer" as one of the possibilities. I looked in both Lee manuals I have and a RCBS manual and NONE mention what a cocked primer is. Can someone please explain what this is?


On a 100 rounds loading of NEW Winchester .38 special brass, the primers seem tilted in the primer pocket. Not enough to stop the revolver cylinder from turning, but they are noticable. I took the rest of the cases and cleaned the primer pocket out but the primers still seem tilted. I also tried my Lee Ram Prime and there still was a tilt but not as much as with the Lee Hand Prime.

The faces of the rams seem flat, although I do not have a surface plate with a decent indicator to check it. They do seem flat though. I also checked and changed the shell plate in the hand prime, same thing, tilted primers.

I also primed some OF brass and they seem tilted as well.

I have not taken these to the range yet, so I do not know if they will have issues or not.

I suspect I am not holding my jaw right or I am grinding my teeth too much when I prime LOL:D

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December 7, 2010, 12:19 PM
Simply put, a "cocked" primer is one that isn't pressed into the primer pocket evenly all the way around, so that it is tilted (or "cocked") off of level; this can be a very mild thing, all the way up to having a primer pressed into the pocket completely SIDEWAYS.

December 7, 2010, 12:25 PM
I have crushed them in sideways and they have not gone off. hard to set one off with a hand primer. I have never managed to do it. I have taken a Lee decapping rod (just the rod/pin) and hammered out (well, more tapped than "hammered") primers with out setting them off. Set the case in a shell holder or on a flat piece with a hole in it and tap that baby right out. Reused them too.

I am not saying to hammer out primers, I am just saying it's hard to set them off without a pretty good pop. ;)

December 7, 2010, 12:47 PM
Before I got the knack of using the Lee I had a few primers in 38 cases that I put in sideways. I just used a 45 sizer die to decap them & seated a new primer.
And I don't notice primers being tilted in the cases using my Lee tool.

December 7, 2010, 12:53 PM
the primers seem tilted in the primer pocket.Caused by a case that doesn't fit the shell holder properly.

Or more likely, a sloppy loose shell holder that doesn't fit case rims properly.

Lee shell holders tend to be on the sloppy side sometimes.
I have had better luck using RCBS or Redding shell holders that fit the cases properly.


December 7, 2010, 01:06 PM
Ahhhh ok makes sense now.... tilted means cocked.....Mine are NOT sideways, just on a slight tilt. Noticable when looking at the seated primer and the primer pocket, the primer is just seated uneven.

Well dang, I have 100 and about 18 loaded. Any danger in shooting them ?

RC- good idea, I will pick up a few RCBS shell holders today for the press and using the "Ram Prime." You are right though, the shells do seem a lil sloppy in the lee #1 shell holders. The thing is, the hand prime and the press shell holders are two different things, the press shell holder does not fit the hand prime. The RCBS will work with the ram prime though.

Smokey Joe
December 7, 2010, 02:19 PM
Kosmic Krunch--The Lee hand primer uses special shell holders--the standard shell holders for a press will not fit. As you have observed.

I'm not fond of the press-mounted primer rams, and beyond trying that when my press was new (many years ago) I haven't used that method.

That said, I've been using the Lee Hand Primer--Lee calls it the Auto-Prime--for many years, and almost all the thousands of primers I've installed with it have gone straight in w/no problems. I have put 2 or 3 primers in, completely sideways with the Auto-Prime, and one upside down, but those were due to my own inattention.

That's the only problem I've ever had with cocked primers.

IMHO, if the primer is inserted into the primer pocket of the brass, all the way, it wouldn't matter if the base of the primer were a little off plumb anyhow, as long as the primer was fully inserted. (i.e. the base of the primer is flush with the base of the case, or better, a little below flush.) In the closed chamber of a firearm, the primer has nowhere to go, and the primer flame has nowhere to go but up through the flash hole to do its duty and light off the powder.

December 7, 2010, 03:23 PM
If the case rim is cocked in a loose or sloppy shell holder, the primer punch will be cocked in relation to the case rim pushing the primer all the way to the bottom and seating it.

The result is "cocked" or unlevel appearing primers after they are seated.



Hondo 60
December 7, 2010, 03:29 PM
I've far too many of these when priming on my Lee Pro 1000.
With this press you have to keep the chute 100% full.
I'm amazed at how mangled they can get & not detonate.

I've finally said to heck with it & stopped using that press (for now anyways)
I bought a 2nd hand blue press (brand new - never used)

December 7, 2010, 04:23 PM
fwiw, i have al lee hand primer. i use it for all my priming. after the first squeeze of the lever i relax my grip a little, rotate the case, squeeze again (the same amount of pressure), rotate again, and squeeze again (same amount of pressure). if you don't move the lever (just relax enough to rotate the case), another primer won't feed and the whole process takes just a little longer than normal. if you do release the lever, either tilt the unit forward to let any extra primers fall back into the tray before you squeeze the handle again.


December 7, 2010, 04:30 PM
My .32 ACP shell holder doesn't hold the case centered. It's a pain. I have another shell holder ordered (RCBS), because I got fed up with it the other day.

December 7, 2010, 06:14 PM
Sloppy shell holders are a pain. I like the RCBS hand priming tool. It uses standard RCBS shell holders. I do not see any "cocked" primers with this tool. One firm squeeze on the handle and it seats them perfectly every time. Just make sure you put the flat end of the punch up. Yes, it will use other standard shell holders too.

Prior to using the hand primer, I used a primer punch on the press. With that, I have put primers in sideways and upside down, but never "cocked". Something has got to be really whacky to put a primer in cocked. You would have to actually deform it. I guess it can be done if the shell holder has the casing held on a slight angle instead of in line with the punch.

December 7, 2010, 07:31 PM
Or more likely, a sloppy loose shell holder that doesn't fit case rims properly.

Turn the case 180 degrees and seat again.

December 7, 2010, 10:10 PM
Ok, I got the RCBS shell holders for the ram prime. They are tighter than the Lee shell holders for sure. I wrote to lee about their hand prime and sent pics of the issue. Maybe I will hear from them tomorrow.

I deprimed about 50 cases and the reprimed with the ram prime unit, all went in straight and just under flush with the RCBS shell holders. I used new primers, I am not brave enough to re-use the deprimed primers.

So now at least I know it is not the cases and was just the uneven seating due to the shell holder.

I might just sell the Lee hand primer and accessories and switch to the RCBS hand primer. Having to buy two different (one for the press and one for the hand prime) same size shell holders blows anyways. At least with the RCBS, I can use standard holders in all operations.

December 7, 2010, 10:25 PM
You can't go wrong with RCBS

December 8, 2010, 03:25 PM
Ok, lee sent me an answer............NOT their fault they said, they said variances in primer manufacturing (eye roll). They warned against using certain primers and said to use CCI or Winchester ONLY. The ones I have done with the RCBS shell holders do NOT exhibit the "cocked" condition.... so I tried a few more with the Lee shell holder and went right back to being "cocked."

I have only ever used CCI, so that is NOT an issue, although I received an email note from my gun shop that CCI primers can corrode and to watch for this. So I guess I look for Fungi and metal corrosion every few months on the primers.

Good call to those that recommended RCBS.

December 8, 2010, 03:38 PM
My RCBS .32 ACP shell holder came yesterday. Works like a champ priming, unlike the other brand shell holder, which is going in the "junk" box.

December 8, 2010, 04:46 PM
I hand seat all rifle primers, I don't want any above the case head.

The tens of thousands of pistol rounds, an amazing amount of them come off the Dillion with cocked primers.

As long as they are not above the case head, I don't have any safety issues.

They go bang and shoot very well.

December 8, 2010, 05:04 PM
I received an email note from my gun shop that CCI primers can corrode and to watch for this.Say what??

I was shooting up some CCI primed .38 Special I loaded in 1980 last week.
I didn't see any fungus amungus growing on any of them.

Hard to imagine any brand of nickle plated primers getting corrosion on them.


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