Pierced Primers on 2nd Firing - New Build

[lazyMlazyK]

Hi guys, I know there are a bunch of threads on here about this, but I think this might be a stumper. I posted other pics a month or so ago of a 6.5 Creedmoor build I did working off a Savage 12 action. I ordered 100 pieces of new small rifle primer Lapua brass for competition use just for this build. I also purchased a Redding S-Type FL Bushing die set, including the match seating die (very nice upgrade, by the way). Before first firing, I FL sized the brass and ran the expander through each piece to make the first seating in this brass possibly more consistent. Worked up some loads, then practice rounds based on a fairly mild load of 40.9gr. H4350 pushing a 140 ELDM. Fired all 100 pieces of brass once. Noticed a little primer cratering, but nothing too crazy. Note, these were CCI 400 primers.

Decided this load shot well enough for now, and loaded all 100 cases up the same as the first firing. So, I started my day today with brass that was about to be shot for a second time. The only difference is, today, I experienced a TON of pierced primers, and those tiny bits of primers getting blown into my bolt, causing misfires and a load of frustration. Temps between the first firing and today were all roughly the same, no huge temp changes. Any ideas on why my rifle was piercing primers today, on the second firing of this brass, and not on the first firing? I'm trying to figure out what caused this, and find a solution. I could definitely try a different primer, if I can find them, but I feel like that's just a bandaid, not a true fix.

The shoot went fairly well for a greenhorn, I placed 11th out of 46 shooters.

 

[GLShooter]

Did you bump the shoulders back to the original unfired state?

Greg

 

[762willdo]

If you load is on the raggedy edge a few degrees ambient temp. Could make the difference

 

[pdhntr]

There can be several reasons, or a combination of them, why you are piercing primers now and not the first time.

However, the CCI 400 has a cup thickness that is .005 less than the CCI 450.

I would not have developed loads for a 6.5 Creedmoor, using small rifle primers with a thinner cup thickness.

Jim

 

[Drop Port]

As stated, you are using a thin cup primer, so it appears you are not piercing, you are "blanking" primers. If it blanks 450 you will need your pin turned down and bushed.

 

[JAlfred]

My opinion is worth even less than what you paid for it, but...

400's are iffy. You can always find someone that says they work fine, but the margin for error is just not there, it doesn't matter if we are talking 223 or 6.5 small primer brass. I use Peterson SR 6.5 Creedmoor brass and stick to CCI 450, CCI BR-4, or Rem 71/2s. Savages tend to have generous firing pin holes, and this does not help your cause.

Your firing pin may have been compromised during round 1 and you did not realize you had already pierced a primer and damaged your FP. This may have caused the problems you experienced in round 2. Pull it and check.

 

[Straightshooter1]

Hi guys, I know there are a bunch of threads on here about this, but I think this might be a stumper. I posted other pics a month or so ago of a 6.5 Creedmoor build I did working off a Savage 12 action. I ordered 100 pieces of new small rifle primer Lapua brass for competition use just for this build. I also purchased a Redding S-Type FL Bushing die set, including the match seating die (very nice upgrade, by the way). Before first firing, I FL sized the brass and ran the expander through each piece to make the first seating in this brass possibly more consistent. Worked up some loads, then practice rounds based on a fairly mild load of 40.9gr. H4350 pushing a 140 ELDM. Fired all 100 pieces of brass once. Noticed a little primer cratering, but nothing too crazy. Note, these were CCI 400 primers.

Decided this load shot well enough for now, and loaded all 100 cases up the same as the first firing. So, I started my day today with brass that was about to be shot for a second time. The only difference is, today, I experienced a TON of pierced primers, and those tiny bits of primers getting blown into my bolt, causing misfires and a load of frustration. Temps between the first firing and today were all roughly the same, no huge temp changes. Any ideas on why my rifle was piercing primers today, on the second firing of this brass, and not on the first firing? I'm trying to figure out what caused this, and find a solution. I could definitely try a different primer, if I can find them, but I feel like that's just a bandaid, not a true fix.

The shoot went fairly well for a greenhorn, I placed 11th out of 46 shooters.

Yeah, those CCI 400's are a little thin, which seems to be a contributing factor. You can go with the thicker 450's or BR4's . . . whenever you might find them these days.

 

[lazyMlazyK]

Did you bump the shoulders back to the original unfired state?

Greg

It didn't appear that the shoulders were even being sized after the first firing, and the die was screwed as far into the press as I could get it. I figured the shoulders weren't blown out as far as they would go due to only being fired that one time. The shoulders measured 1.560" after sizing to be loaded the second time. I just measured a case fired today and it is 1.5635".

**EDIT - The 1.5635 measurement was before decapping. Must have been a little bur on the primer, as after decapping, cases measured 1.56"-1.561" base-to-shoulder. I think I remember making a slight adjustment midway through sizing some of the brass after first firing - this would correlate with the loaded rounds I measured last night at 1.5585" base-to-shoulder.

 

[Catfur]

Using ordinary small rifle primers (vs. small rifle magnum primers) on a 40+ grain capacity, modern (i.e. 65K PSI) case, seems like a recipe for primer problems. Remember that ordinary small rifle primers are (or were, anyway) based around hornet/bee type cases, and that the prototypical magnum small rifle cartridge leading to magnum primers was the 222 Remington family.

 

[boltfluter]

Many of the primers appear flat indicating to me that they were blown back against the bolt face. Many times the firing pin will "bounce", for lack of a better term, piercing the already thin primer cups. I would check your headspace compared to new brass, and seat into the lands
.010 or so, to hold things in place for the first firing. Check your firing pin tip for damage. Good luck!

 

[deadidarren]

I still cannot get my head around firing more than 2 cases with blown out primers .
I would be bushing firing pin hole and reprofiling firing pin

 

[Bc'z]

I still cannot get my head around firing more than 2 cases with blown out primers .
I would be bushing firing pin hole and reprofiling firing pin

Or shoot large primer brass

 

[NorCalMikie]

NEVER have had issues blowing/piercing primers with CCI.
Maybe fired 5000+ with no issues. And NO I don't bush the firing pins.
Second firing? Shoulders pushed back too far when sizing.
Firing pin pushes case forward in the chamber, round goes BANG, case gets slammed back against the bolt head, primer tries to back out of the pocket and gets "pierced/blanked" by the firing pin.
It's a Savage. Either snug up the head space or don't push the shoulders back.
If the fired brass will re chamber with no resistance, neck size, load and go shooting.
You rolling your own ammo? Build it to fit "your" gun.

 

[dellet]

As others have stated, it’s a primer issue. I would add a couple thoughts.

First would be referring to your load as “fairly mild”. Both Hornady and Hodgdon place it at or over max for that weight bullet. Not really an issue, but when combined with a CCI 400, it starts to make sense why you have the problem. Basically a 60,000 psi load and a 40,000 psi primer.

Remington is probably the best at noting pressure limits on their primers. 1 1/2, 6 1/2 both warn against High pressure loads. There has been a lot written and speculation that CCI 400 SRP and 550 SMP are the same primer.

This is probably one of the best articles written on the subject and is often quoted , the thickness chart listed earlier came from this and was also featured at one time in the Accurate Shooter bulletin.

Primers And Pressure

As for why no problem one day and big problems the next., that’s why why some people say 400’s and high pressure loads are fine, and some say you’re crazy for using them.

One thing I would note would be rate of fire and barrel temps. Were you you shooting faster, longer at the match?

Looking at your cartridge box I wonder if there is a pattern there.

Did you start at the front row and work back?

Note the rate of failure in each row. More or less 10% failure in the first row, 10% not failing in the rear.

Good for finishing well into the top 25% on a first go!

 

[jcm800]

Common with 400's and high pressure loads. If you look closely at a blackened primer you will see a tiny hole in bottom. A hot jet of gas has cratered the tip of your fireing pin. Polish the fireing pin tip to remove this crater or your problem will continue.....switch to 450's or another thick cup primer.

400's are nothing more than a magnum pistol primer. Use them as such.

 

[Nick Caprinolo]

Since you have loaded unfired cartridges, pull the bullets and recheck your powder load.

What I see is most likely a bold and firing pin problem. It appears to me that many of your primers show they are being struck off center and others are exactly on center. Further, most of your primers are cratered which can be caused by a sloppy firing pin hole in the bolt. You may need to have your bolt sleeved. I have been using CCI 400 small rifle primers in my Lapua 6.5 brass for several years and have never experienced a problem. When I save never, I mean not one time. You have no need for magnum primer in this caliber.

 

[lazyMlazyK]

As others have stated, it’s a primer issue. I would add a couple thoughts.

First would be referring to your load as “fairly mild”. Both Hornady and Hodgdon place it at or over max for that weight bullet. Not really an issue, but when combined with a CCI 400, it starts to make sense why you have the problem. Basically a 60,000 psi load and a 40,000 psi primer.

Remington is probably the best at noting pressure limits on their primers. 1 1/2, 6 1/2 both warn against High pressure loads. There has been a lot written and speculation that CCI 400 SRP and 550 SMP are the same primer.

This is probably one of the best articles written on the subject and is often quoted , the thickness chart listed earlier came from this and was also featured at one time in the Accurate Shooter bulletin.

Primers And Pressure

As for why no problem one day and big problems the next., that’s why why some people say 400’s and high pressure loads are fine, and some say you’re crazy for using them.

One thing I would note would be rate of fire and barrel temps. Were you you shooting faster, longer at the match?

Looking at your cartridge box I wonder if there is a pattern there.

Did you start at the front row and work back?

Note the rate of failure in each row. More or less 10% failure in the first row, 10% not failing in the rear.

Good for finishing well into the top 25% on a first go!

What edition Hornady book are you looking at? My 10th edition lists 41.5gr H4350 as max for the 140 ELDM. I guess I never really thought about the pressure ratings on primers, but that makes a lot of sense. I've completely stripped and cleaned the bolt, and everything really looked pretty good, aside from being absolutely filthy with carbon.

Started at the front row, working back. Each string was a string of six shots, fired within 3 minutes, then about an hour wait my your next shots.

 

[SKWERLZ]

1-cci 400’s are really for cartridges like 22 hornet and questionable for pressure above 50k

2-fired brass tends to need less powder for a similar pressure than new brass.

 

[dellet]

What edition Hornady book are you looking at? My 10th edition lists 41.5gr H4350 as max for the 140 ELDM. I guess I never really thought about the pressure ratings on primers, but that makes a lot of sense. I've completely stripped and cleaned the bolt, and everything really looked pretty good, aside from being absolutely filthy with carbon.

Started at the front row, working back. Each string was a string of six shots, fired within 3 minutes, then about an hour wait my your next shots.

Hornady #9. It does not list the ELD.

I did note that it has different max charges for H4350 @ 40.9 and IMR 4350 @ 41.5.

Hodgdon also has different max loads for both.

Again not a big deal, but it shows that the load might be closer to the high end of things than you expect. Different components, chambers etc.

Kind of looking at all possibilities. Note post #16 by Nick Caprinolo, never an issue. You really get this argument with AR 15 shooters using 400’s.

I shoot a lot of antiques, smokeless loads in original blackpowder cartridge rifles. Using low pressure rated primers, such as a Remington 1 1/2, is very helpful. One to insure the weak hammers can set them off. But also having a primer flatten at 30,000 psi helps keep loads safe.

Primer construction and limits are good info to have and use to your advantage.

 

[Nick Caprinolo]

Always check the data from the bullet manufacturer. They are the ones who know and test their products the best.