Dimples in the primers

C

Clubster

New member
Quick question for those in the know.... What causes tiny dimples in a primer while seating? Some have dimples and some do not. Using CCI large magnum pistol primers.
 
Something wrong with the shell holder like if it's bent or twisted or if there's a little sliver of brass swarf in between the shellholder and where it mounts up into the priming tool. Also check that the primer installation Ram is flat and smooth and undamaged. I assume you're talking about the little Half Moon marks?
 
Ive had a flake of spilled powder stick on the face of the in press primer seater. That has caused small indention in the primer. A quick swipe with a cleaning brush (tooth brush) fixes it.
 
I cleaned it and I am thinking it's the little ball powder of H110 doing it. Tiny little marks, not slivers ect. I will run it again tonight and will se if the cleaning helped. had to pick up more primers so couldn't test yesterday.
 
Photos are always helpful. I have found that an old RCBS hand primer was doing that. I tried the Lyman hand primer tool, which requires Lyman shell-holder, solved the problem. You can probably ignore them, or, try a different priming method.
 
Your Priming Tool ... Look at the seating stem , make sure the priming punch is Flat and Smooth ... You may need to file / sand it perfectly flat and polish smooth .

I had a tool (Lee) that had a little "tit" left on the priming punch ... just enough of a protrusion to set about every third primer off ... Rattled My Nerves when they popped !!! I had NO idea what was happening ...
the man at the gunshop , who sold me reloading tools , took it apart , showed me the little "nub" then knocked it off with a flat file and polished the punch end with a piece of #600 abrasive paper ... never had another primer go off after he did that !
Gary
 
So a shallow primer pocket wont cause the primer to dent the primer when seating primers on a press.
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Not if you are operating the press or primer seater correctly. This is not a slam it in thing, its a slow push and when the primer bottoms out, you stop pushing. Your tool should be set up so you can feel it.

If the primer bottoms out and still stands proud (in a too shallow pocket), you should resist the temptation to smash it in deeper, until it is flush, or below.

IF you do, probably nothing more than some surface deformation will happen, but the best thing to do is take the out of spec case out of your loading cycle. Then decide if it is repairable (primer pocket reaming) or if its not worth the effort.

IT is possible, if not common that "overseating" the primer can fragment the primer pellet, which may cause erratic ignition or failure to ignite. You can't tell until you fire it, if the problem exists, so its good to avoid things that might cause it, even if the probability is low.
 
Also possible to have a piece of dry tumbling media that falls out of the case onto the priming punch
 
Also possible to have a piece of dry tumbling media that falls out of the case onto the priming punch
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Doesn't happen if you inspect your brass the way I do.

After decapping (and usually sizing) I tumble my brass to remove the case lube, and dump the tumbler into a colander with a bucket underneath. Stir the brass to separate the media, then I inspect each case including verifying the flash hole is clear (I use an old horseshoe nail to poke out any stuck media) and there is nothing (media) left in the case.

Each case is checked for flaws, clear flashholes, being empty, and then measured before it goes into the loading process. Been doing it that way for over half a century, has always worked for me.
 
Dillon press and the cases were once fired then cleaned with old primer still in case.
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+1 on case prep and inspection before sitting at your press and loading.
A progressive press is not where you want to discover problems. I advocate doing all case prep before loading.
 
Running a Dillon, I assume you are decapping at the first stage. In that case, I suspect the particles that leave the small indentations may be primer residue that didn't all fall into the primer catch with the spent primer cups and instead were jostled loose by machine vibration as the shell plate went around and then stopped.

Decap your primer separately, or else resize and decap it in the press and remove the case from the press just before it advances to the primer or primer/charging (depending on the press model) station. Retumble the brass to clean out the primer pockets, clean the press, and try again, this time slipping the sized cases into the shell holder on the up-stroke just before the shell plate turns (or you turn it on a 550). That should end the pattern on the primers if the residue is causing it.
 
one other thought, it's not that the op would do this, but changing from small to large primers without changing the press tool can do that too.

just a thought.
 
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