Beretta 92 Pierced Primers

[Nacho Man]

Hey guys need some input here. I bought a lightly used Italian made 92Fs for my lady. We shot a box a few weeks ago using rem umc and it runs fine. Today we shot some magtech ammo and we got some pierced primers. Ive never encountered this before but then again I only collect about 50% of my brass. Heres a pic
https://s32.postimg.org/5t2avbkgl/20160728_161438.jpg
These are the cases from last time we shot it. I inspected the gun and did push the plunger and checked the fp when I bought it. Didn't notice anything abnormal about the tip. Theres a coulpe stray cases in silver but the rest are from the gun. I did not shoot the gun today, my lady did. I was busy playing with my 1911 lol. Didn't experience any malfunctions.
https://s32.postimg.org/93yqxqnkl/IMG_58391.jpg

[James K]

The top box shows signs of a light firing pin blow. The bottom box, also has an odd look, probably same thing. I think the "light use" you mention included someone reducing the mainspring (hammer spring) tension to make it easier to fire the gun double action. Replace the mainspring with the correct one and the problem should go away (but the DA trigger pull will be heavier).

The "pierced" primers are often thought to be caused by a too heavy mainspring; not true. They are the result of too light a spring which does not give the hammer enough momentum to keep the firing pin from backing out and allowing the primer to push back through the firing pin hole.

After you resolve the problem, be sure to remove the firing pin and check for any brass "discs" from primers that might be in there to interfere with the firing pin at some later time.

Jim

[Nacho Man]

well to honest the pull on dbl action feels pretty heavy like stock to be me 10-12lbs. just like when I had my 92 compact. The cratering is caused by a bevel at the breach on the fp hole. I understand most italian made berettas have that while the us models do not.

[James K]

The factory bevel at the firing pin hole is small and is not the cause of the "pierced" or bulging primers.

Jim

[Nacho Man]

another member on a board told me beretta 92 uses a spring retracted firing pin and the hammer doesn't hold the fp against the primer, inertial type.
Ive read some reports of magtech primer ruptures on other forums as well.

[James K]

Of course the Beretta 92/M9 uses a firing pin spring; so does the Model 1911. In any of those guns, inertia keeps the firing pin in the primer until the pressure drops enough that the primer won't flow into the firing pin hole. If it does, there is something not right.

A bit of "slop" is tolerable, but if pieces of primer are blown back into the firing pin tunnel, they will eventually jam the firing pin and hang up the gun. And that is not going to have a good outcome. I have no idea what Magtech's standards are or what someone might have said they said, but anyone who says blown (pierced) primers are somehow "normal" is giving bad advice.

Jim

[TunnelRat]

I'm a bit confused. So my General Physics is a bit rusty, but we seem to be mixing units here. We have Pressure which is Force/Area, or MassxAcceleration/Area and Inertia which is the resistance to changes in motion and is directly relatable to mass or mass times distance squared if you mean a moment of inertia. Directly relating pressure and inertia doesn't account for everything at play. What about other forces such as the force of the firing pin spring returning the firing pin to its original position?

I'm just not sure we've got the whole picture. And while the silver primers appear to have light strikes, as would be expected from a light hammer spring as you mentioned, the vast majority of the gold primers seem just fine from what I can tell on my phone. For that matter I've had issues with light strikes on pistols from reduced hammer springs and I've never had pierced primers. I feel like it could be a combination of factors.

I did find an article in Shooting Illustrated that touches on this.
https://www.shootingillustrated.com/articles/2012/2/16/problems-with-primers/

Sent from my iPhone using Tapatalk

[James K]

Well, all that he really said was, "There are a lot of variables at play here."

Yep.

But not counting a sharp firing pin that will actually punch a hole in the primer (and that takes a bit of force - try it with a dead primer), a hole in the primer where a piece has been blown out is always (or at least I know of no exceptions) due to the pressure in the primer blowing the little disc through the firing pin hole. That can be caused by pressure from the main powder charge OR from the primer internal pressure, which is from the pressure of the primer compound exploding.

But it is not usually due to high cartridge pressure, but to a light firing pin or a light firing pin blow that allows the firing pin to be blown back. I have seen it in guns with light firing pins, light hammers, or light firing pin springs (when the spring drove the firing pin forward).

Jim

[tangolima]

The cratering on the primers, both the magtech and Remington, is too much to my liking. Over sized firing pin hole is not kosher. Firing pin tip should be shaped as a hemisphere without sharp point and sharp edges.

Magtech ammo is not my favorite. I would be rather desperate when you see me using them. I don't even want to shoot them for plinking.

-TL

[Mike38]

My Beretta 92FS leaves the same type of dents on primers of ammo shot in it. No piercing, but the same kind of crater that resembles over pressure. I figured it's because the firing pin hole is large, and is chamfered a bit. So the primer face flows back into the chamfer. It does the same on factory ammo as well as my light reloads. I do have a reduced power hammer spring in my. Never gave it a thought, and not really concerned. I've shot thousands upon thousands of rounds without a problem.

[Nacho Man]

well first things first. pierced primer, im inspect the tip of the fp take a pic so everyone can see as well. im pick up two other brands of ammo like ppu, fiocchi or herters etc and go fire them. if i encounter another pierced primer the gun is going to my smith. I'll take another pic of the exit hole for the fp as well.

[Nacho Man]

http://uploads.tapatalk-cdn.com/20160802/a64544408c0d7663c18093b54730dc76.jpg
http://uploads.tapatalk-cdn.com/20160802/40fa24ccc4d761362f9a01669f6cebc7.jpg
http://uploads.tapatalk-cdn.com/20160802/38785b1a222dc9f09cfd3e0931b56882.jpg
http://uploads.tapatalk-cdn.com/20160802/950c3da255ae0b3af62d5f5314f4ca08.jpg
http://uploads.tapatalk-cdn.com/20160802/13b6ee886d25d426826e035ef4f873d0.jpg
http://uploads.tapatalk-cdn.com/20160802/3693557569d6703d9525bbb89fdb2bda.jpg

[tangolima]

There is a concave "ring" on the breech face around the firing pin hole. I remember reading about Beretta's solution to feeding problem. That could be it. With that the cratering on the primers is "normal".

The firing pin hole doesn't seem over sized compared to the firing pin. So we are good.

The only potential issue is the shape of the pin tip. It seems conical rather then hemispheric. Can't make out on the pictures, but is there a tiny sharp point at the apex of the tip? Anyway, if it was my pistol, I would shape the tip to a smooth hemisphere.

I think the pierced primers is mostly likely problem of the particular brand of ammo. I have had pretty bad experience with magtech. Won't use them again if I have a choice.

-TL

[DaleA]

I've got no answers here just lurking to take in the knowledge.

Thanks James and others who have posted. I would not have thought a lighter mainspring would result in primer problems. Now, not only do I know that it could happen someone explained how it could happen.

Nacho Man---those are some nifty close up pictures that show what you are talking about. Did your camera have a 'macro' setting or maybe I should just ask how you did it?

[Nacho Man]

cellphone

[James K]

All I can say is that IF those blanked primers were fired in that gun, you WILL have some problems at some time. Those little brass discs do not magically disappear. They are going somewhere and a good bet is that they are back in the firing pin tunnel waiting until there are enough of them to jam the firing pin.

Plus the hot gas from the primer going the same route will eventually erode the firing pin tip into a point.

Then someone will blame the "pierced" primers on the "sharp" firing pin and (of course) on the ignorance of Beretta in making their firing pins too sharp.

Jim

[Nacho Man]

you guys think its safe to fire

[tangolima]

I don't think anybody can tell you whether the pistol is safe to shoot. For sure pierced primers is not safe, so at least it is not safe with the magtech ammo.

-TL

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[243winxb]

Pressure venting at 38,500 PSI is never good.http://www.saami.org/specifications_and_information/specifications/Velocity_Pressure_CfPR.pdf or safe.

[James K]

Before firing again, I would remove the firing pin and clean out the firing pin tunnel. Use a .22 brush and/or anything you have to get any crud out that hole.

In your first picture, there appears to be something in that firing pin hole besides the firing pin (at about 1:00 in the picture), so I would check that out first.

If you have changed the mainspring (hammer spring) or firing pin spring, go back to the originals ones. If all seems OK at that point, I think you will be OK.

Jim

[Nacho Man]

I wonder if I should buy a factory spring kit and drop it off at gunsmith near work.

[James K]

Let him buy it; he will make a couple of bucks and you will make a friend.

Jim

[Nacho Man]

mind as well. i wanted to replace the recoil spring anyways with a new one

[243winxb]

After enlarging the pierced photo, the center of the primer is still there. Gas came from a tiny pin hole in the primer. Had same in 357, replaced the hammer nose (firing pin) after many years. Not as dangerous , like when the center of the primer is gone. Avoid the problem ammo and keep shooting, while keeping watch on the firing pin tip.

[amd6547]

My Magtech experience involved 30 Carbine ammo. Several times in a box of 50, primer fell out of the fired brass. I discovered it when a primer ended up in the left bolt lug recess and prevented it from going into battery. Never happened with any other brand.
Since my Taurus PT92 happens to be next to me as I look at the breech photos, I had to look at the Taurus breech. No concave on mine, and it doubt it helps feeding.

[tangolima]

My Magtech experience involved 30 Carbine ammo. Several times in a box of 50, primer fell out of the fired brass. I discovered it when a primer ended up in the left bolt lug recess and prevented it from going into battery. Never happened with any other brand.
Since my Taurus PT92 happens to be next to me as I look at the breech photos, I had to look at the Taurus breech. No concave on mine, and it doubt it helps feeding.
That is exactly what happened to me; m1 carbine. From then on, I don't touch their stuff if they pay me.

-TL