Concave Primers, Academic Question

[JPB4BAMA]

Anyone have an idea why primers would go concave after firing? Seen them flatten, blank and all the other stuff from high pressure, but i've started to see some that are concave. All of these are rather low pressure loads, QL calculated around the 45kpsi range. Seems to do it on all on the first fire forming loads on a new batch of pre primed Norma brass, but also seeing it on a smattering of "regular" loads that I've been trying to work up while trying the Bosnian Ginex primers.
I was thinking that maybe they were not fully seated and the firing pin was deforming them before they ignited, but I question that after measuring the pre primed stuff pretty consistent at 5 to 6 below the case head, and if I try to "reseat" them they feel firm in the pocket and won't go deeper without the primer ram deforming them. On my reloads with the Ginex, they are @ 4 below, and that is actually quite a chore, so I doubt the pin could drive them in any more.
Silver is the pre-primed FF load and the Brass is the Ginex load.

 

[Dusty Stevens]

Low pressure and a weak fp spring

 

[Rocketvapor]

I'm trying some of the Ginex SRP and find the 0.020" thick cup flattens just a little bit more than the 0.025" cup of the CCI 450.
All shot with same (NOT a light load) in my 22 Nosler.

 

[6.5 forever]

Low pressure and a weak fp spring

I think Dusty is right on track.

 

[Dusty Stevens]

I think Dusty is right on track.

Happens every time

 

[NorCalMikie]

Maybe "slight" headspace issue with the brass in the chamber.
Primer tries to back out of the pocket when fired and gets pushed back in by the firing pin.

 

[JPB4BAMA]

Happens every time

Thanks, I am sure that the pressure has something do do with it, but the dynamics am not sure of. I don't think my spring is weak, as only a few of my normal loads show this, whereas all of the FF loads do. Also, I have never had any issues with FTF even with the CCI 450, CCI 41 or Rem 7-1/2. Might be missing something, but there are no indications that I am smart enough to watch for. Now I do know that I probably should have my firing pin hole sleeved as it is obviously a bit too big as evidenced by the cratering even at such low pressures, but it's still OEM as is the spring.

Thanks

 

[Ggmac]

Is it a Savage with the new firing pin spring ?

 

[JPB4BAMA]

Is it a Savage with the new firing pin spring ?

No, this is a Remington 700.

 

[JPB4BAMA]

I'm trying some of the Ginex SRP and find the 0.020" thick cup flattens just a little bit more than the 0.025" cup of the CCI 450.
All shot with same (NOT a light load) in my 22 Nosler. View attachment 1416743

Thanks for the comment. I did not know the cup thickness on the Ginex. They would deform when seating similar to what I sometimes see with winchesters, but they are so stiff going in I was not sure if it was thicker, harder or what. I did shoot just a couple of my hotter loads and also saw similar flattening, but nothing I was worried about yet, so this helps with confidence working up.
Now on another note, on my standard load that is actually really rather light I saw a pretty significant difference in MV SD between the CCI450 and the Ginex, about 1/2, with the Ginex being the better of the two. CCI's typically yield in the upper teens to low 20's, and the Ginex run right around 10. I would not bet the bank on them yet, but it sure is a promising start.

 

[Dgd6mm]

You could have the bolthead bushed and replace the firing pin spring if needed.

 

[Rocketvapor]

I will be trying some more next week.
Here is a somewhat cherry picked 300 yd 10 shot group (best of the day) with the Ginex SRP.
0.65 MOA is pretty good for me.

 

[6.5 forever]

Hey Ticket, good shooting!

 

[Webster]

Anyone have an idea why primers would go concave after firing? Seen them flatten, blank and all the other stuff from high pressure, but i've started to see some that are concave. All of these are rather low pressure loads, QL calculated around the 45kpsi range. Seems to do it on all on the first fire forming loads on a new batch of pre primed Norma brass, but also seeing it on a smattering of "regular" loads that I've been trying to work up while trying the Bosnian Ginex primers.
I was thinking that maybe they were not fully seated and the firing pin was deforming them before they ignited, but I question that after measuring the pre primed stuff pretty consistent at 5 to 6 below the case head, and if I try to "reseat" them they feel firm in the pocket and won't go deeper without the primer ram deforming them. On my reloads with the Ginex, they are @ 4 below, and that is actually quite a chore, so I doubt the pin could drive them in any more.
Silver is the pre-primed FF load and the Brass is the Ginex load.

I have been shooting my Rem 700 since 1969. On my 4th barrel. I see no reason to spend the money on sleeving the FP. I believe it's just cosmetic. I like to see the raised area around the indent increase with increasing the powder. I have a feel for when it's getting close to max. You mention your FFing 223. Do you mean the first firing on the new cases? Are you seating the primers by feel to the bottom of the pocket? What's difference between an unfired case and after shooting on a bump gauge? My guess is the FP is pushing the primer and or case forward giving less FP impact. energy. Easy to eliminate these possible issues.

 

[JPB4BAMA]

I have been shooting my Rem 700 since 1969. On my 4th barrel. I see no reason to spend the money on sleeving the FP. I believe it's just cosmetic. I like to see the raised area around the indent increase with increasing the powder. I have a feel for when it's getting close to max. You mention your FFing 223. Do you mean the first firing on the new cases? Are you seating the primers by feel to the bottom of the pocket? What's difference between an unfired case and after shooting on a bump gauge? My guess is the FP is pushing the primer and or case forward giving less FP impact. energy. Easy to eliminate these possible issues.

I am fireforming to 223 Ackley. All of the initial FF loads are on the lighter side to try to work harden the brass. As for seating. In the initial post, where I see this the most is the lot of pre-primed Norma brass I just got, but I did try to seat them further, and I believe they are all the way in. As for my own primed with the Ginex primers where I saw this, that's a good question - they are so stiff to seat there is no "feel" other than a cramp in my hand, so I'm relying on depth measurement to make sure they are in enough, and this is not a FF load, just a lighter load for the cartridge -- early test of the primers not knowing how they would act.

 

[JPB4BAMA]

Low pressure and a weak fp spring

Not to dispute one with more knowledge and experience that I, but Why? I don't understand why low pressure would cause a primer to blank. I can sort of understand a weak spring, but there again I would think I would see other symptoms of this on other primers, especially FTF on Magnums or MIL-Spec?

But I have to follow up and understand this as today I had one blank on a moderate load and it killed my Jewell trigger. That load was the attached Quickload run, however this particular single shot was me again trying the GINEX primers that seemed to shoot just fine on my initial work up. I personally think its the primers as some of the other ones I dolled out to others also saw some blanking, I think they are too thin and going in the back up pile for low end pistol loads or even the trash, but your comment and subsequent support makes me have to ask for the explanation of why this combination would lead to this.

Pardon, my ignorance, but in this case I certainly am totally ignorant.

Thanks for any education

JPB

 

[Dusty Stevens]

Not to dispute one with more knowledge and experience that I, but Why? I don't understand why low pressure would cause a primer to blank. I can sort of understand a weak spring, but there again I would think I would see other symptoms of this on other primers, especially FTF on Magnums or MIL-Spec?

But I have to follow up and understand this as today I had one blank on a moderate load and it killed my Jewell trigger. That load was the attached Quickload run, however this particular single shot was me again trying the GINEX primers that seemed to shoot just fine on my initial work up. I personally think its the primers as some of the other ones I dolled out to others also saw some blanking, I think they are too thin and going in the back up pile for low end pistol loads or even the trash, but your comment and subsequent support makes me have to ask for the explanation of why this combination would lead to this.

Pardon, my ignorance, but in this case I certainly am totally ignorant.

Thanks for any education

JPB

The weak spring causes the pin to bounce. Not enough pressure lets them not fill out

 

[JPB4BAMA]

Is it a Savage with the new firing pin spring ?

Please elaborate on this question. Reason being, that as I follow up on Dusty's comments which actually relate to my Remington, I have an friend that is shooting a new Savage 6BR, and he was also trying out the Ginex primers I distributed and had half a dozen pierced primer in a row. This follows his very successful test of the same primers in his Remington 223 FTR rifle that resulted good precision and three successive strings of sub 10 SD. The jury is still out on the primers as some of the results are very good, but this piercing issue is still of great concern.

 

[shoot4fun]

Not to dispute one with more knowledge and experience that I, but Why? I don't understand why low pressure would cause a primer to blank. I can sort of understand a weak spring, but there again I would think I would see other symptoms of this on other primers, especially FTF on Magnums or MIL-Spec?

But I have to follow up and understand this as today I had one blank on a moderate load and it killed my Jewell trigger. That load was the attached Quickload run, however this particular single shot was me again trying the GINEX primers that seemed to shoot just fine on my initial work up. I personally think its the primers as some of the other ones I dolled out to others also saw some blanking, I think they are too thin and going in the back up pile for low end pistol loads or even the trash, but your comment and subsequent support makes me have to ask for the explanation of why this combination would lead to this.

Pardon, my ignorance, but in this case I certainly am totally ignorant.

Thanks for any education

JPB

Loads that produce low end pressure don't allow the brass to expand quick enough to grab the chamber walls. The results can vary but usually you see primers that just look "different" and may have hard bolt lift due to the backward thrust of the case.

 

[JPB4BAMA]

The weak spring causes the pin to bounce. Not enough pressure lets them not fill out

OK, thanks. I'm on board with you, but now it seems that there are several weight classes of springs, any recommendations - 223AI bolt. My "go to" primers of choice are Fed 205M, CCI 450 and Rem 7-1/2 if that makes any difference.
Thanks