Excess headspace and primer piercing

[Doug Beach]

Perhaps instead of “excess headspace”, I should say excess longitudinal case body clearance, in order to avoid conjuring Guffey.
In any case, is primer piercing a reasonably expected consequence of excess headspace, on the order of .008-.010”?

 

[243winxb]

is primer piercing a reasonably expected consequence of excess headspace, on the order of .008-.010”?

M~mmm let me guess. No. 50/50 chance of being correct.

 

[shoot4fun]

May I hazard a guess that the action is a Remington 700?
If you're aware of that headspace issue and size your brass accordingly then you should not have any issues at all.
Last question; how do you know it is "on the order of .008-.010?

 

[Someoldguy]

Long story, but I encountered an excessively long chamber in a bolt action 5.56. The short for chamber case length resulting from using reloading techniques described in the instructions that came with the dies caused protruding primers when fired, but none were pierced. They were CCI SR Magnum primers, so they might be thicker than a standard primer. (?)

 

[Cloudrepair]

Perhaps instead of “excess headspace”, I should say excess longitudinal case body clearance, in order to avoid conjuring Guffey.
In any case, is primer piercing a reasonably expected consequence of excess headspace, on the order of .008-.010”?

Do you have a headspace gauge to verify the difference?
Are the primers cratering?
What is the firing pin protrusion?

 

[Cloudrepair]

Some things to consider
Have you measured the case head of a fired round and unfired round is there any moisture in chamber or on rounds?
What is the charge?
I ask because these are all thing you should know and I would want to know if I was trying to figure this one out if I wasn't sure
I have fired many different rifles with what I would call headspace issues and have not had primer piercing issue.

 

[Zero333]

0.010" HS clearance will not pierce a primer. At least it never did it to me when I accidentally sized a couple pieces of brass to far.

Try CCI primers. Unless your primer blanking is happening with cci primers.... the problem is most likely due to the firing pin size, or protrusion, or pin has too much wiggle room bolt face ( needs to be bushed ).

 

[NorCalMikie]

Excessive head space, (brass problem NOT chamber problem) you pull the trigger, firing pin pushes case forward in chamber,round fires, primer starts to back out of pocket, firing pin hits and pierces primer and pushes said primer back into pocket as the case head slams back against the bolt head, making you believe you've got a pressure problem.
Once round is fired, case if fire formed to chamber. No more issues with pierced or "blanked" primers "unless" you push the shoulder of the case back too far when sizing. Then, you're starting all over again.

 

[Uncle Ed]

Perhaps instead of “excess headspace”, I should say excess longitudinal case body clearance, in order to avoid conjuring Guffey.
In any case, is primer piercing a reasonably expected consequence of excess headspace, on the order of .008-.010”?

What caliber cartridge and what primer are you using?

Below a CCI 400 primer with a .020 cup thickness fired in a AR15 rifle.

 

[NorCalMikie]

Any cartridge/caliber. They'll all act the same way with excessive head space.
The more head space, the worse it may be.

 

[jpx2rk]

Would a primer not fully seated give the same end result???

 

[gunsandgunsmithing]

Some things to consider
Have you measured the case head of a fired round and unfired round is there any moisture in chamber or on rounds?
What is the charge?
I ask because these are all thing you should know and I would want to know if I was trying to figure this one out if I wasn't sure
I have fired many different rifles with what I would call headspace issues and have not had primer piercing issue.

Can also be a weak fp spring. Cheap and easy fix that I like to do every couple of seasons regardless. May also be a combination of contributing factors. Pressure is typically NOT one of them. The case pictured above does not show any signs of pressure, imho.
The most likely cause id the clearance and/or the shape of the fp hole. Savage is bad about having somewhat of a "funnel" around the hole and Remington....they're just plain terrible about poor pin to hole fit and some have a chamfer around the hole. That was a terrible idea.

Piercing a primer is usually the result of a crater that goes beyond the yield point of the brass the primer is made of. Instead of a puckered fp strike on the primer, the brass stretches further than it can and simply tears, resulting in the indentation and surrounding brass coming out...or piercing, which is a bad name for what really happens. It's not pierced but rather stretched to the point the brass around the fp completely fails.

 

[dkhunt14]

The only two CCI BR4 primers I ever saw blanked was caused by two things. One was bumped too much and the other was a weak firing pin spring.

There can be other things like too much space around the firing pin or a bad pin. Matt

 

[243winxb]

Has any one had a pierced/blanked primer when firing factory ammo in a factory rifle, when shooting a bottle neck type cartridge?

I think Not.

 

[dkhunt14]

Has any one had a pierced/blanked primer when firing factory ammo in a factory rifle, when shooting a bottle neck type cartridge?

I think Not.

My guess is that has more to do with oversize chamber and long freebore. Matt

 

[NorCalMikie]

Most factory ammo is shorter that SAAMI trim length. You'll get the same thing. Once fired,brass forms to chamber and if you don't push the shoulders back too far and start the whole issue all over again, resize, reload and go shooting. Easy way to correct that issue is to increase the OAL of the round by pulling the bullet out a bit and jamming it into the lands. Once fired, the brass is formed to the chamber. From there, resize and being sure you don't push the shoulder back too far, reload and go shooting. Long freebore not an issue. You just can't get to the lands. Load to mag length.
In a gas gun, be damn sure you know what you're doing when it comes to reloaded/reloading ammo. OAL too long and you run the chance of a "slam fire".
I HAVE loaded gas gun ammo long but I planned it that way and knew what to expect.

 

[Larryh128]

Perhaps instead of “excess headspace”, I should say excess longitudinal case body clearance, in order to avoid conjuring Guffey.
In any case, is primer piercing a reasonably expected consequence of excess headspace, on the order of .008-.010”?

In my opinion only, it probably won't cause it but I surely would correct it to .002-.003.

 

[Nature Boy]

I have a Savage that recently blanked a primer. It's got some FP hole slop like most Savages so everything ends up a little cratered, however, this blanked primer happened the first time I tried CCI 400 primers.

Went back to Fed 205M and all is good again. CCI 400 + excess FP hole clearance = pierced primer.

 

[Bill K]

Has any one had a pierced/blanked primer when firing factory ammo in a factory rifle, when shooting a bottle neck type cartridge?

I think Not.

Beg to differ with you on that. I had two boxes of a factory loaded 223 Rem brand and out of the 40 rounds, I stopped shooting them when out of the first 10 rounds fired, 8 pierced the primers. I pulled the bullets on the rest and reloaded the brass, with some of my own loads..

 

[Texas10]

Has any one had a pierced/blanked primer when firing factory ammo in a factory rifle, when shooting a bottle neck type cartridge?

I think Not.

Sure did! Brand new model 12V in 223 blanked just about anything I put in it, including mild hand loads. Turned out the firing pin had about .007 clearance with the bolt head firing pin hole. Replaced the firing pin and that guns shoot dots now.