Flattened Primers?

[Viss]

I'm still a greenhorn to reloading and have been moving along with great caution for the last year.

It seems to me that all my 357 mag loads have primers that appear to be flat. I have never seen flattened primers personally so I don't really know what i'm looking at.

I apologize for the poor pictures, but my photo equipment and skill are lacking.

Can anyone tell if this is a sign of overpressure.

Thanks for any replies

 

[john traveler]

Your primers do not look overly "flattened". Flattened primers loose their outter radius. Yours still look normal.

What your primers do show are some "cratering" and extrusion. Not a good thing! Two of the primers also show some gas leakage, from the dark firing pin imprints. A weak mainspring can cause the cratering, as well as a damaged firing pin bushing.

I would take a good look at the tip of the firing pin or hammer nose. Any chips or defects there will give the signs you have. Also, continuing to fire the gun and getting those leaky primers will erode the firing pin tip, making it get worse, quickly.

Higher pressures are not the only thing that will flatten primers. Excessive headspace (cartridge-to-recoil shield) will do it too.

 

[john traveler]

Your primers do not look overly "flattened". Flattened primers loose their outter radius. Yours still look normal.

What your primers do show are some "cratering" and extrusion. Not a good thing! Two of the primers also show some gas leakage, from the dark firing pin imprints. A weak mainspring can cause the cratering, as well as a damaged firing pin bushing.

I would take a good look at the tip of the firing pin or hammer nose. Any chips or defects there will give the signs you have. Also, continuing to fire the gun and getting those leaky primers will erode the firing pin tip, making it get worse, quickly.

Higher pressures are not the only thing that will flatten primers. Excessive headspace (cartridge-to-recoil shield) will do it too.

Try firing some factory ammo and compare the primers. If they still look the same, chances are good the problem is with the gun, not the ammo.

Also, early M686 guns were recalled for firing in bushing prolblems that caused hard extraction and prime extrusion. Give S&W a call. Don't mention that you fired handloaded ammo.

 

[Wee Hooker]

Yea, what John said.. Both times

 

[Titegroups]

Maybe it's just me, the ones in the bottom photo sure look flat. Flattened primers are just what they sound like, flat. The radius will be gone on the primer and the back will be very flat except for the firing pin indentation. Also be aware of difficult extractions.

 

[Viss]

Thanks for the replies, there is no outer radius on the primer it is flat.

I looked at some 38 spl cases I fired and they have the outer radius.

The rounds in the picture are 14 gr. 2400 with 158 gr. lswc 18bhn with federal small pistol primers.

I also loaded 6.1 gr unique with 158 gr lswc 12bhn with same primers and they all look the same.

All rounds extract easily out of my 586, The rounds in the picture were fired from a Rossi/Puma rifle. Thanks again for your input.

 

[alwslate]

Your loads do not seem to be excessive. Make sure your primers are
fully seated. Primers that are just a bit high will flatten upon firing
and may leak or puncture.

 

[fredj338]

Thanks for the replies, there is no outer radius on the primer it is flat.

I looked at some 38 spl cases I fired and they have the outer radius.

The rounds in the picture are 14 gr. 2400 with 158 gr. lswc 18bhn with federal small pistol primers.

I also loaded 6.1 gr unique with 158 gr lswc 12bhn with same primers and they all look the same.

All rounds extract easily out of my 586, The rounds in the picture were fired from a Rossi/Puma rifle. Thanks again for your input.

They do not look flattened. A flattened primer looks like par tof the case, just a diff color. I cans see the dividing line & a very slight radius, even w/ the fuzzy photo. Federal primers have a rep for being "soft". A heavy firing pin spring or too sharp a firing pin will indent the primer like that. Your load of 6.1gr of Unique is certainly no where near a max load.

 

[OKFC05]

The rounds in the picture are 14 gr. 2400 with 158 gr. lswc 18bhn with federal small pistol primers.

You answered your own question.
If you use Federal magnum small pistol primers, they will not distort so much. The regular Federal small pistol primers are soft. I loaded some .380 using them and the primers looked worse than yours. The same loads with WIN primers looked normal.
By the way, pressure signs in straight-walled pistol cases are notoriously misleading and hard to read. Just follow good loading manuals in your loading and don't get too creative.

 

[Steve C]

The cratering you see is from the primer flowing into the firing pin hole. This may or may not be a sign or increased pressure. If the firing pin hole is excessively relieved you can see this with normal pressures and a good test is to see if the same thing appears with factory ammo used as a standard.

 

[Viss]

Thank you all for the great information and advice.

I did shoot some factory ammo and they didn't look as flat. I have heard before about the Fedral small pistol primer being softer than others, and my manual calls for small pistol in the 357 mag. Thanks again, I feel better about these loads now.

 

[MWAG]

i load mine where they'll barely come out of the cylinder and the primers are very flat