Firing pin cracked

[Alx]

" In essence, with a broken pin, it is fully extended, un-contained, and really pushes on very little, if anything at all... "

This is not making sense to me .... When assembling the firing pin into the gun, and compressing the spring with the retainer, there is quite a bit of pressure, even with the pin all the way forward, sticking out past the bolt-face. Even with a broken firing pin, broken in half, there is no way the metal can escape being there .... the stack of firing pin pieces is the same length as before, or longer if the break is jagged and the forward part of the pin twists. If the skirt of the cup is what is broken off, and the sear bar holds back the rear part of the pin which is merely then a sleeve, the front of the pin is still under the spring pressure.

Given that the spring would not have enough pressure to dent the primer cap at rest, still the intertia of the bolt slamming the primer with the pin's point could cause firing. Without the sear holding back the entire pin when the action closes, you have a dangerous situation. But if the pin were broken in half, with the break in front of the spring cup, and the gun went into battery with the sear holding the back of the pin as it is supposed to, there might not be enough inertia for the front half of the pin to fire the gun. Maybe that is how your pins broke, and why the gun did not fire.

[alanint]

That was my feeling. Somewhat like an MP40 bolt setup.

[ithacaartist]

OK, well. somebody will try it with just the front end of a firing pin installed, and we'll see. I think it will fire.

[G.T.]

Hi guys, well I was working on memory and so, just went to the bench to see if I could determine what actually happened at the range... here's what I found out at the bench.. I took out all my firing pin springs that I have in stock, a dozen plus... and I find that there is a 3/8" variance in free length between the longest and the shortest... I don't know if this would factor in, but you again are correct that there is some spring pressure even with the broken pin and shortest spring... although still nothing like the tension power of the spring tension when compressed approx. 3/8"with a good firing pin locked on the sear notch...But, again, the broken firing pin is not pushed, or released, (or held) by anything?? The breechblock carries it, but does not allow the transfer of inertia necessary for the now, less than half as heavy firing pin, to strike from near zero forward movement ?? To further complicate things, I think the loading case rim, is pushing the firing pin back flush before it ever goes into battery, thus simply resting, sliding, against the primer throughout the whole chambering process?? Otherwise I believe, it, (the cartridge) would jam against the protruding pin point?? At any rate, it didn't fire for me on failure, and on the next round, or the next?? On two occasions... .. next one might go off.. but I really hope we never see that!..... It was an Erfurt! Might have been the whole issue... BTW, one of the pins broke right smack dab in the middle... almost as if cut... I'm sorry to say, I can't remember if it marked the primer at all, like an AR will sometimes do... I looked, just can't remember... it was WW box ammo... Get out your hacksaws boys! ... Best to all, til...lat'r....GT BTW, An MP / Uzi, anything bolt is probably 100 times, or more, the mass of a complete Luger firing pin, with a rock solid pin point, and it's coming in, all the way from center field!!!... BTW, David, I'm betting it don't! lets set up a pool!

[G.T.]

Hi Alx, In reading more of your post, I think the reason for the breakage might be two fold, and some of it my fault... the first time, it broke immediately and may have already been fractured, and other then being numbered, old dark and dirty I have no idea.. the second pin broke right thru the number as well, but I was shooting 9MM NATO ammo and was having all kinds of issues until the firing pin broke and the day was done... It wasn't visibly broken when I started and I had looked at it upon a prior inspection. it was a matching gun too! I just don't trust any / all junky WW1 firing pins anymore... ... best to all, til...lat'r...GT

[G.T.]

I have an idea, (dangerous all by itself!) which I will try later this week..... I am going to the range, and will remove the sear bar and hold open.... then with one round in the mag... pointed down range, I will release the toggle and see if it goes off, and if I was just lucky! Or otherwise...... best to all, til...lat'r...GT

[alanint]

Let's hope we don't have to start calling you "one eye", GT!

Good luck! It should be an interesting contribution to Luger lore!

[G.T.]

Hi Alanint, yes! I am wondering the very same thing.... will the mass of the full firing pin make a difference??... I don't think so... but I am worried! Maybe should have a camera ready for the surprised look that will most likely be on my face!!...... ...best to all, til...lat'r....GT

BTW, I'm also going to try it with a cartridge in the chamber for a direct head on strike? Maybe negating the scrubbing effect of loading.... .... interesting if nothing else!

[Alx]

I have the impression that Luger in full auto mode will empty its full magazine in what appears to be one slightly prolonged instant, all one sound .... the fastest machine gun after a MGxx, Hugo and Georg having basically adapted the Maxim machine gun action for semi-auto ....

[G.T.]

Yes, if it does go off, with a full mag...it would be uncontrolled mayhem...but as I'm only going to use one round at a time... Even I should be safe???... to a degree.......til..lat'r...GT

[John Sabato]

My Money says that GT's experiment will not result in a slamfire...

I think the the firing pin would need the momemtum of a sudden full fall powered by the firing pin spring to result in a discharge with a locked breech.

If the front portion of the firing pin is broken free of the sear surface, I think that when the breechblock slams home, loading the cartridge from the magazine on it's way, that the firing pin spring will actually cushion and soften the blow of the firing pin and a discharge could not be depended upon... UNLESS you are using reloads with civilian grade small pistol primers... sealed Military primers take a good smack to set them off.

Just my $0.02 worth of mechanical engineering experience... take it or leave it. The test will tell the story.

[alanint]

Uh, Oh! G.T., break out those soft commercial pistol primers. We want to hear a bang!

[rhuff]

Originally Posted by G.T.

Hi Alanint, yes! I am wondering the very same thing.... will the mass of the full firing pin make a difference??... I don't think so... but I am worried! Maybe should have a camera ready for the surprised look that will most likely be on my face!!...... ...best to all, til...lat'r....GT

BTW, I'm also going to try it with a cartridge in the chamber for a direct head on strike? Maybe negating the scrubbing effect of loading.... .... interesting if nothing else!

GT,

If you want to do it the safest way possible, then just resize some fired 9mm brass, and prime them with a fresh primer. Then you can chamber it with the toggle open, and allow the toggle train to slam forward. No powder or projectile to worry about. If it pops the primer, it would fire the cartridge. You could do this in your shop. Just a thought.



PS...If you can't resize fired brass, then just remove the bullet and powder from a loaded round. The result will be the same.

[ithacaartist]

Originally Posted by G.T.

Hi Alanint, yes! I am wondering the very same thing.... will the mass of the full firing pin make a difference??...
BTW, I'm also going to try it with a cartridge in the chamber for a direct head on strike? Maybe negating the scrubbing effect of loading....

Gerry, as you indicated in your story, sometimes it would fire, but mostly not? I wasn't intending to say that it would be rock-solid dependable ignition under these circumstances, but I'd estimate it to be at least as dangerous as dropping a de-cocked Luger.

A handy way to replicate the broken firing pin might be to snag the front half of one that's been on eBay, listed without mention of its condition as original f.p.! Using the entire firing pin might be tipping the scale to the "bang" side.

Releasing the action on the chambered, primed-only round sounds the safest way to go. It would avoid eating up the energy needed to strip the round from the mag and scrub it into the chamber, again, maybe a tip of the scale towards a bang.

You know, I hope we're all a little bit right--that dropping the toggle, say, a dozen times, it will have gone off a couple of times. It's like Xmas morning, waiting to see how this experiment turns out!!!

[Lugerdoc]

GT, As I understand it, you are using a FP that doesn't catch on the sear (trigger bar). THis could be caused by either of these part being worn or damaged. In most cases, this alone would not cause the pistol to slam fire. Tom

[G.T.]

Hi Tom, well sort of.. our thread is about a firing pin that broke in half and caused the weapon to just not fire??.. our discussion stems around the issue as to whether or not the weapon could have discharged from slamming home with a broken in half pin, the second of two such failures I have experienced.. neither time could I make the weapon go off by re-cocking and reloading until I discovered the broken pin... Maybe I was just lucky...we will see tomorrow as I try to replicate the failure by removing the sear bar, and just loading one round in the mag at a time... BTW, drop me an email, I need to inquire about some of the items you have mentioned... and some others I need! best to you Tom, til...lat'r....GT....

[G.T.]

Well, just got back from the range and my test fire with the sear bar removed, toggle slammed shut, produced NO slamfires!!! out of 10 attempts, and I think with 99% certainty, that it will not go off with a separated firing pin, as long as the front part isn't lodged in the breechblock for some un-known reason?? I also tried it a few times with a cartridge in the chamber and a direct impingement of the pin on primer in a slam fire condition, same results.. no bang.. BUT, it did mark the primer in every instance, just as I surmised with AR type firearms... So, there you have it boys! Can't go off unless the firing pin drops from a sear release........Best to all, til...lat'r....GT

[ithacaartist]

Good work, G.T.!! Thanks for the ed-ju-macation!

[G.T.]

Hi to all! I was kinda surprised myself?? I had the prior experience of the failures, or I would have thought the same way.. And, again, nothing to ever take lightly! I think a large % of inadvertent discharges, come during, or just after a malfunction...... Sooooo, always keep it pointed downrange!! BTW, I would have tested more, but the range officers were starting to look at me with a puzzled expression?? Thought it time to move on... .. Best to all my forum friends! til...lat'r....GT

[John Sabato]

Originally Posted by alanint

Uh, Oh! G.T., break out those soft commercial pistol primers. We want to hear a bang!

Ahah! My theory is vindicated!