Pierced primer...

K

kolineman

New member
While shooting this past week, I experienced a pierced primer for the first time ever...

I was shooting factory ammo, Hornady Vmax stuff, 55 gr. loads in my 223. Rifle is a Weatherby Mark V, Super Varmint Master. This is the first time I've ever had any primer issues of any sort, just wondering what could have caused it and what possible damage could have been done that I may not be seeing.

Any thoughts on possible causes? I've fired a few hundred rounds thru this rifle and never had an issue. I plan on taking it in to my gunsmith this week and have it looked over....

Thanks in advance.
 
Often a firing pin issue

Pierced primers are often a result of a firing pin issue. Either too flat or too pointed. Sometimes the distance the pin travels into the primer cup as well. Although I did have some Remington primers once that many people on the firing line were complaining about but that's rare. If you have shot the remainder of the ammunition without incident I wouldn't worry about it. Just dismantle the bolt and clean out any of the residue which can act like grinding paste.
 
The only damage that I think could happen is that the piece of primer might keep your rifle from firing at a charging bear. Do what Andy said....take you bolt apart and search for any pieces. Look in the firing pin hole as that is where those pieces like to live. If you continue to have this problem you'll need to fix it whatever it is...too much powder, weak spring, firing pin too large, etc...

That said, once upon a time I was winning the nationals...one more group to go. While I was wiping my bolt off I noticed a primer doohickey in the firing pin hole. When cleaning it out I found my bolt was full of them darn things. I cleaned them out, shot a big one and ended up 6th.
 
Thank you guys...

Thank you Andy and Wilbur, taking things apart this afternoon to take a look. I didn't have any issues following this, but I only fired a few more rounds of different factory ammo. Hopefully all is good. I will let ya know what I find.
 
Possibly you had a primer that was a shade too thin or maybe you somehow had something get into the firing pin hole which would in effect be the same as a slightly longer firing pin. Since it happened once with factory ammo, I'd not get too excited. Clean the bolt as recommended by the other posters. Maybe put a note in the box about it and contact the ammo manufacturer if it happens again.
 
In a couple of extreme cases

In a couple of extreme cases I saw the bolt face needed to be cleaned up after repeated pierced primers occured. One would think they would have stopped firing the rifle in these cases even if they may have been in competition ??????
 
pierced primer

I don't shoot competition but I always thought Winchesters had the softest cup. I don't know what kind of primers are in Hornady ammo. Do they make their own? Making primers is quite an operation. Doug
 
Primers

Yep you're quite right. Making primers is a far more intricate job compared to making bullets or powder. The active ingredient is cyclotrimethylenetrinitramine also shortened to RDX. This actually is an explosive unlike smokeless propellant. Which always amazes me that we do not need an explosives licence ( here in Oz ) to purchase them. The equipment they are made on has to be constantly calibrated to maintain the delicate balancing act. The manufacturers purchase the primer cup material in sheets made by third party suppliers to their specifications. This is why the hardness of the cup material varies from one manufacturer to another. The hardest cups I have found were CCI BR which also measure the largest in diameter. The softest I've found to be the 7 1/2 remington. Any time I have had a pierced primer was because of a firing pin that needed attention.
 
primer hardness info

some interesting information
 

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  • Small Rifle Primer cup hardness and thickness.docx
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primers

Speaking of how hot primer mix is, they just had a primer mix house blow up at Lake City killing one and injuring 2. I always thought those primer mixers were in the house by their selves. I don't know how the other people were hurt. I guess they got too close. Primer mix is what we called it at Lake City RDX was fuse powder. Primer mix was touchier than RDX. Doug
 
Doug.
Thanks for that info....Just never realized it....
I have watched vids of LC and other companies.............
LC is making Billions of rounds a day....They seem to have a pretty good safety record/rounds made.....
Never thought to git a job there. Maintenance wise...Looks impressive.....Oh, well...The best ammo for the Best Military, this planet has ever seen...
 
Yeah your right

Doug Casner said:
Speaking of how hot primer mix is, they just had a primer mix house blow up at Lake City killing one and injuring 2. I always thought those primer mixers were in the house by their selves. I don't know how the other people were hurt. I guess they got too close. Primer mix is what we called it at Lake City RDX was fuse powder. Primer mix was touchier than RDX. Doug
Click to expand...

Yeah your right. They start with basic RDX but chemically enhance it by reducing the amount the energy level has to be raised to cause it to detonate. A bit like when they enhance nitro cellulose which is already quite flammable to make smokeless propellant. Did that explosion make the national 6 o'clock news or wasn't it news worthy enough ? In Oz the media would cash in on something like that for weeks.
 
LC primers

Sorry guys, I went turkey hunting yesterday and didn't look at the computer. That fatality made the local news buy I don't know about national. I worked in the 7.62 building a long ways from the primer assembly where it was a lot safer. I made cases. About all you had to worry about was a cut or a smashed finger not getting blown up. I rode to work with a girl who worked where they made the fuzes that's the only way I knew the difference between RDX and primer mix. She always said primer mix was easier to set off than RDX. The static electricity in your body will set off primer mix. They rubbed the mix in the primers in water. Doug
 
Andy Cross said:
Yeah your right. They start with basic RDX but chemically enhance it by reducing the amount the energy level has to be raised to cause it to detonate. A bit like when they enhance nitro cellulose which is already quite flammable to make smokeless propellant. Did that explosion make the national 6 o'clock news or wasn't it news worthy enough ? In Oz the media would cash in on something like that for weeks.
Click to expand...

The nitrocellulose disassociation reaction has to be slowed down to make smokeless powder.

Straight nitrocellulose is a high explosive.

I worked part time in a lab once that measured the nitrocellulose concentration in old WW2 cannon powders destined for reprocessing.

They often only had 20 to 30% by weight of actual nitrocellulose.

We needed to estimate how much of the powder was needed to make a 'cake' of the correct size.

After very careful grinding solvents dissolved the nitrocellulose and then the solvent was extracted leaving better than 99% nitrocellulose.

The final product was a cake about 14 inches across and 6 inches thick.

The processing equipment was operated by compressed air in a very flimsy building by remote control from a blast proof concrete building.

The cakes then where moved in trucks to another part of the plant to make solid rocket motors.


One truck exploded and the frame was driven many feet into the ground through the asphalt road.

Nothing much was found of the driver.

A pierced primer can allow a jet of powder gases to escape.

It can pit and erode the firing pin.
 
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Well actually

The nitrocellulose disassociation reaction has to be slowed down to make smokeless powder.

Straight nitrocellulose is a high explosive.

Well actually according to my friend who is a chemical engineer nitrocellulose isn't classified chemically as an explosive. The law sees it differently. It just burns aka a redox reaction very rapidly. The grade used in making smokeless propellant doesn't have to be as high as the material you worked with. It's slow by comparison and they enhance it to make the faster propellants. Many of the propellants used to launch navy salvos etc used a mixture of materials some of which are explosive.
 
Andy Cross said:
The nitrocellulose disassociation reaction has to be slowed down to make smokeless powder.

Straight nitrocellulose is a high explosive.

Well actually according to my friend who is a chemical engineer nitrocellulose isn't classified chemically as an explosive. The law sees it differently. It just burns aka a redox reaction very rapidly. The grade used in making smokeless propellant doesn't have to be as high as the material you worked with. It's slow by comparison and they enhance it to make the faster propellants. Many of the propellants used to launch navy salvos etc used a mixture of materials some of which are explosive.
Click to expand...


"The law sees it differently"

And in this case the law wins.


Methane is technically not an explosive either.

Ever seen the results of an natural gas explosion?


Mixing in various retarders allows control of burning rates.

Most of the additions in the manufacture of smokeless powder (including nitroglycerin, nitroglycol, and other nitrated fuels) are to increase the energy content.


Priming mixes mainly rely on lead styphnate but can also contain aluminum, TNT, azide compounds, and other energy sources.


The development of shrunk barrels for naval guns allowed very large compressive forces to be applied to the inner layers of the barrel.

This means that a large gun can easily survive pressures that would rupture the steel used to make the barrel.

As the barrel sits the outer layers are exerting millions of PSI on the inner layers.

The explosive needs to overcome these stress-strain forces in the assembly before the metal sees any stress from the propellant pressure.
 
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