Pierced Primer Damage

[Uncle Buck]

In another thread people are talking about potential damage caused by a pierced primer.

Specifically a small pistol primer used in a rifle cartridge.

Can the same thing happen in with large pistol primers and rifle cartridges?

Does anyone have any pictures of what actually happens to the bolt face and the cartridge?

Thanks.

 

[SonOfGun]

I do not have a pic to post but pierced primers will cause erosion (flame cutting) of the bolt face/firing pin hole.

 

[m&p45acp10+1]

I had a Remington standard SR primer that was mistakenly used in a .223 Rem case. It pierced, Left some cabon on the bolt face of my Savage. as well as a black smear on the firing pin. Also I had to use a cleaning rod to extract the case.

As far as Large I am not sure, I am led to believe that Large Rifle Primers are taller than Large Pistol Primers. Using a pistol in place of the rife the primer may be too deep for the firing pin to strike.

 

[243winxb]

Pierced Primer-Bolt Face-Photos

Photos in my albums. I had to replace the hammer nose on my S&W M28 357 after many years. Pierced primer make little pock marks in the nose. After many, it becomes shorter, causing misfires. The rough nose can damage primers, making them fail also. This was using standard & magnum pistol primer. When the bolt face is damaged, the primer blows out on the rounded edge of the primer. The one i have had were defective primers. See the bolt face of my old M16A1 in photo albums. http://www.photobucket.com/M16A1 http://www.photobucket.com/joe1944usa

 

[F. Guffey]

UIncle buck, pierced primers, there is the .7854 principal.

Pierced primers, a weak firing pin spring can guarantee a pierced primer, not a balancing act but the pressure on the firing pin must be greater than the pressure inside the primer/case. When the pressure is greater inside the case/primer the pressure pushes the firing pin back, when the firing pin is pushed back ‘far enough?’ the dent in the primer becomes a hole, and that is when the hot, high pressure, metal cutting gas cuts the face of the bolt around the firing pin hole.

And that is where the crater term comes from, the primer becomes a mirror of the bolt face, firing pin and hole around the firing pin, when a creater appers, descriped as a dent with a high ridge around it damage has been done.

Normally, the firing pin crushed the primer with a big dent, then the pressure inside the primer forces the primer to conform to the firing pin, again, if the firing pin spring can not exert enough pressure on the firing pin the firing pin moves back. Then there is the nail effect, the nail does not make a good firing pin, the firing pin is designed to crush the primer, I have rifles that have firing pins that are not bashful about crushing primers.

F. Guffey

 

[brickeyee]

Can the same thing happen in with large pistol primers and rifle cartridges?

You are a lot more likely to notice this error.
Large rifle and large pistol primers are the same diameter, but large pistol is not as deep.
It would be WAY below flush in a large rifle pocket.

Small pistol and small rifle are much closer to identical in all dimensions.

If you did seat a large pistol in a rifle pocket and could get it to go off (it wil be pretty far in) it would cause the same type of damage.

Erosion of the firing pin, breech face, etc.

 

[jimbob86]

Erosion of the firing pin, breech face, etc.

Also, depending upon how the escaping gas is vented, other bad things can happen ...... with my 93 Mauser, I had superficial powder burns on my left thumb, and the cocking piece rebounded and whacked my right thumb right where the thumbnail starts to grow ...... painfull, that.

 

[243winxb]

Pierced Primer

2 kinds of pierced primers. There is a pin hole in the dead center of the primer where the pin hit. This flame cuts the firing pin nose. Primer stays in one piece. The 2nd type is where the metal of the primer thats indented breaks free on the edge of the strike. This little disc can be pushed back into the firing pin channel. This disc is pushing the pin backwards from high pressure. As most all pressure goes thru the pin channel, the bolt face may not get gas cut. This disc can bind the fining pin, causing miss fires. Or the disc can get in the action and jam the gun.

Pierced or Blanked Primers.

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1. Check the firing pin, it should have no gas cutting or deformities. 2. Firing pin protrusion should be checked. Internet search shows .055" to be about right for an AR15. Check with a gun smith as each firearm might be different. 3.The firing pin must stay in contact with the primer on firing. A weak hammer spring on an AR or a weak firing pin spring like on a Rem 700 bolt action will let the firing pin rebound on primer piercing when the hot gas pushes the pin backwards. 4.If the hole the pin sits in is to larger in diameter, the primer flowes back into this hole till the center of the primer separates and fall into the action or travels into the firing pin area. Bushing the firing pin hole will fix this. Or you may want to try a magnum primer with a thicker cup. Military ammo may have a crimp that needs to be removed before seating a new primer. The crimp is removed by shaving or swaging the primer pocket. Swaging may be needed here so the prime can be seated lower in the pocket. High primer = misfires & pierced primers. There is also a high pressure sign visible. The reloader was using a "starting" load and CCI 400 primers. The pressure sign may have formed on firing the factory ammo. I just shot some XM193F factory, the web area expanded .0015" on firing. This is a sigh of a "hot" load.

 

[Lost Sheep]

Broke parts, jammed gun

My friend was shooting his 500 Smith & Wesson revolver (Buffalo Bore) and his gun tied up tight.

We shoot it around enough to open the cylinder and get it unloaded, but sometimes the action could cycle and sometimes it wouldn't.

Eventually, it went to a local gunsmith, S&W repair center, who opened it up and found part of the sear mechanism had broken off, jamming other parts from moving. He also declared that the firing pin spring had lost its temper and the firing pin itself needed to be replaced.

A pierced primer had allowed the pressure to blow back against the hammer and break the part, and the hot gasses had cooked the spring and firing pin.

Smith & Wesson made good on their warranty. He has cooled on his enthusiasm for Buffalo Bore.

Lost Sheep

 

[snuffy]

Do you want to see for yourself?

IF you have a AR boltface you want to replace, AND some Remington 6½ small rifle primers, load some max loads in .223 brass, then shoot about 20 of them. Those Rem. primers will pierce at the edge of the FP dent, the flame cutting around the FP hole in the boltface will be easily seen. ASK ME HOW I KNOW! It cost me a new bolt for my buddies AR. Worst part was paying for something I didn't then get to use.

I never borrow something I can't afford to own if I damage something. I expect the same from anybody else I loan something to.

 

[Uncle Buck]

Thanks guys. I knew you would come through on this one.

Not looking to replicate any-ones experience, but I knew you guys would have the answer.