Strange phenomenon with my primers.

[RIDE-RED 350r]

Hello everyone.

I am new to reloading and so far everything is going pretty well except for one thing.

When I look at my primers on spent brass, I am getting a slight dimple in the primer inside the actual firing pin strike dent. It is very small, almost looks as if the hammer may be bouncing and making that second mark.

The rounds are 38spl, 125gr Nosler JHP over 5.2gr of Unique

I am getting this in 2 different Smiths, a m36-7 and 19-3. Both have hammer mounted firing pins.

This is definitely not primer cratering. The primer isn't rising up around the firing pin dent. It's simply a small little dent inside the main dent. Almost looks like a defect or small piece of debris on the firing pin. But I can find neither issue with the firing pin

I do get this with my reloaded 357 mags out of the m19 as well. Those were 140gr Hornady XTP over 15gr Alliant 2400

I have heard that Federal primers are softer than most and those are what I am using.

Also, I never paid much attention to my spent primers when I was using factory ammo. But now that I am beginning to fire my first reloads, I am checking for signs of over pressure. So, now I am looking at them. Maybe this is normal and I just never noticed before??

I have a couple of pics, but it's difficult to really see it clearly in the pics compared to holding the case in your hand....The pics make it appear more severe than it is

I have looked at pics of many examples of cratering and am confident this is not the issue I am having.

I have searched the web for this issue of the secondary minor dimple and have come up empty handed.

Also: these loads are right out of the Hornady book. They are not at start load specs, but not at max either. I will not go over max.

Can you tell me

A:Is this a problem at all?
B: If so, what is the issue and what do I do to remedy it.

I hope this isn't what would be considered a dumb question and a waste of time for the more seasoned handloaders to help me with.. I just want to make sure I'm not doing something wrong here...

Thank you.

 

[robertrwalsh]

Just for the hell of it fire a couple of primed cases with no load in them. That will give you an idea if it is pressure related or not.

 

[jwalts27]

I too use Federal primers and checked my spent brass. No dents like that, but I shoot an M&P 40, not revolvers.

Sent from my Samsung Tablet

 

[lebomm]

Looks to me as if the primer cup is being crushed against the anvil particularly hard. As long as the primers are not extruded or heavily flattened, I think I would not worry about it.

Larry

 

[MichiganScott]

Check the nose of your firing pin with a magnifying glass. You may have pierced a couple of primers sometime in the past and flame-cut your firing pins.

 

[RIDE-RED 350r]

I will check the firing pins of the m19 and m36 closer with a magnifying glass.

I will also try popping a few primers in empty cases. I thought about trying that. Definitely a good test to see if the issue is pressure related.

I just fired these rounds the other day and this has been urking me. I was going to wait to check with you folks but I was too anxious to see what ideas and advice might be given.

Also I forgot to mention, none of those dimples actually pierce the primer.

And thank you all for the input. I appreciate it.

 

[rwsmith]

No piercing

Looks to me as if the primer cup is being crushed against the anvil particularly hard. As long as the primers are not extruded or heavily flattened, I think I would not worry about it.

Larry

And no piercing. Since Feds are soft it's very likely the surface is being formed against the anvil.

 

[Nevada Ed]

+1 on a firing pin "Pimple"............

Had the same with my 270 and finally just replaced the imperfect face of the pin after 15 years of use, it also needed a new firing spring to stop weak primer strikes.

The end of a firing pin should look like a round nose bullet.....
no sharp corners or bumps that can rupture a primer.

 

[Rpg]

I suspect you are seeing the anvil impression.

 

[ArchAngelCD]

I would also take a good look at both those firing pins.

Please keep us updated...

 

[jepp2]

Just for the hell of it fire a couple of primed cases with no load in them. That will give you an idea if it is pressure related or not.
Reply With Quote

Generally it isn't a good idea to just fire the cases with the primers in a revolver. They tend to back out when fired and can tie up the cylinder. The pressure build backs the primer out of the pocket. When shooting a normal load, the bullet forces the case back against the recoil shield and reseats the primer.

 

[scooter123]

Generally it isn't a good idea to just fire the cases with the primers in a revolver. They tend to back out when fired and can tie up the cylinder. The pressure build backs the primer out of the pocket. When shooting a normal load, the bullet forces the case back against the recoil shield and reseats the primer.

In a somewhat left handed fashion I suspect that this is the cause for your "double dimple". The primer strikes you round and causes the initial dimple and then the casing backs into the firing pin as the powder charge ignites.

That 5.2 grain load of Unique is actually rather light for a jacketed bullet and well below the 5.7 grain Do Not Reduce load listed in the Speer #14. BTW, a 5.6 grain load of Unique will produce about 850 fps. from a 4 inch 67-1 so you may want to consider increasing your charge weight.

I saw something sort of similar with my 625 yesterday. Started out by shooting loose rounds in the cylinder without moon clips and then followed up with 16 clips of ammo. The difference in the depth of the resulting dimple was actually startling, because those loose rounds sit a bit deeper in the chambers than ammo restrained by moon clips. By sitting deeper that meant that the firing pin was projected further forward when the case backed up to the recoil shield. May take pics of the difference and put it up in a separate post as a brain teaser in the smithing section. Because the dimples on those loose rounds give new meaning to the word Deep.

 

[RIDE-RED 350r]

Thank you for that advice Scooter.

I had trouble finding data specifically for the Nosler 125gr JHP. I used the data for the 125gr Hornady XTP found in our Hornady loading manual. I'm not sure what issue, but we got it with our press kit a few months ago.

I don't have the book in front of me, but I seem to remember Hornady listing 5.8gr as max before getting into +P for the 125gr jacketed bullet.

I will double check my manual.

 

[RIDE-RED 350r]

Update:

Guys, it seems as though this is a non-issue and fairly commonplace.

I happened to be looking at a box of empty factory 357 brass fired out of my father's m19-3 and guess what...same little dimple. Just a little more faint, but definitely there.. Winchester ammo, obviously Winchester primers. And I see alot of info about the Fed primers I am using being softer than the rest.

Another bit of reinforcement to my theory this is nothing to worry about... A friend gave me a partial box of Winchester factory 38spl to try out and see if I get the dimple with those too.. Well guess what? His 586 left the same mark on those fired factory loads as well...

So I guess I just never noticed this happening because I never used to look at the primers on fired factory ammo. Now that I have begun reloading, checking for signs of over pressure caused me to notice something for the first time that has most likely been occurring all along.

Thanks to you all for the advice and ideas!

Happy reloading!