Fluted firing pins

[wlyon]

When was the fluted firing pin introduced? I have sources listing 1934 and another 1923. I have a 1921 dated police luger with a matching fluted firing pin. Thanks Bill

[Vlim]

Wylon,

Difficult to say. The problem is that on surviving blueprints it's impossible to make out whether the firing pin was fluted or not. Also not a lot of documentation from the DWM 1921-1930 era survived (or if it did, it's not available). I believe the general consensus is that the fluted firing pin was a Mauser improvement and that would place it in 1934. Of course, firing pins will break and correctly numbered replacements will be found in pre-1934 guns, without doubt.

[Ingvarg]

Hi.

Sorry I kidnapp the thread, but what is the advantage of the fluted firing pin over the older unfluted one ?

Maybe a bit stupid question, but the most stupid questions are those never asked, so..............

[alvin]

Originally Posted by Ingvarg

Hi.

Sorry I kidnapp the thread, but what is the advantage of the fluted firing pin over the older unfluted one ?

Maybe a bit stupid question, but the most stupid questions are those never asked, so..............

No question is stupid, IMO. Sometimes, I heard people talking some jokes in parties and everyone laugh, I sit there and did not feel funny at all, but everyone else laugh, I thought "should I do the same?" That thought made me feel stupid

I assume the flute firing pin was designed to reduce the chamber pressure when it's too high. Experts please correct me if I am wrong.

[alanint]

I believe the flutes were placed there as channels for debris to accumulate as well as a gas channel. Accumulated debris can freeze the firing pin in the extended position creating a full auto Luger for the duration of cartridges in the magazine.

[alvin]

Originally Posted by alanint

Accumulated debris can freeze the firing pin in the extended position creating a full auto Luger for the duration of cartridges in the magazine.

Just thought it again..... debris definitely could prevent firing pin from moving forward freely because the firing pin string could only offer relatively weak force, but it's unlikely to block the pin from locking on the sear during the recoil cycle. Recoil force is big. So should the sympthom be mis-fire instead of slam-fire?

====

Yet another advantage that I imagine on fluted firing pin .... it reduces the contact area between the pin and the round pin hole, so the pin is less likely to get stuck in winter. Many guns go even further, they use triangle pins.

[alanint]

I think all of the above were taken into consideration when altering the firing pin with channels;
1) Inability to fire due to debris
2) Full auto fire due to debris
3) gas channel for overpressure loads

[John Sabato]

as to #3 in the reason list above... I think the firing pin improvement flutes were to provide a gas release without harm to the pistol in the event of a blown primer.

[jamese]

John has it correct,
the fluted firing pin was designed to allow gas pressure to escape in the event of a pierced primer, without damage to the weapon or operator.

Jim

[Lugerdoc]

John S, is right again. On many Finnish lugers you will also find a hole drilled into the bottom of the breech block as a pressure relief vent, to prevent the old style FP from acting as a piston and blowing out the back of the breeck block. TH

[tenbears]

Maybe a fluted firing pin would have prevented this damage.

[Ingvarg]

Thank you all for this info.
According to "tenbears" pic. it looks like it would be clever to replace the firing pin in my Luger with a fluted one.

[Mauser George]

Reason for fluted firing on Mauser produced Luger's.

Early DWM Luger's did not have a fluted firing pins as they were not needed. Reason being that the front of the chamber (I cant recall the dimensions) was machined to have a smaller ID diameter than the rear of the chamber. When a round was fired this would make a good seal at the end of the mouth of the case and seal the chamber so there would be no blow back into the breech block.

Next time you fire an early Luger you will notice that the mouth of the case has a smaller OD than the rest of the spent case. You will also notice that the spent case is relatively clean and not covered with black residue. Again this is due to no blow back in the rear of the chamber.

When Luger production started at Mauser, they eliminated this feature to speed production. With the blow back being forced into the breech block it was breaking firing pins, hence they started fluting them to assist in the gas escaping the breech without damaging the firing pin.

I am not able to recall where I read this, however next time you fire an early DWM Luger check the dimensions of the case and you will see what I am referring too.

Merry Christmas!

Regards,

George

[Dwight Gruber]

I must continue to express a contrary opinion to that of my friends here on the Luger Forum.

The "stepped" chamber was patented in 1910 by Georg Luger (although it was in use in 9mm Parabellums earlier). It's purpose was as a seal, to keep the chamber free from unburned powder residue.

The 2-part chamber machining was in constant use until 1941, when it was replaced with a smooth chamber, presumbly to reduce the complexity, and therefore the time and cost, of manufacture.

The fluted firing pin was patented by Georg Luger in 1893, explicitly to keep a firing striker clear of grease and oil residue. The feature was added to P08 production by 1934. If you examine a Luger with one of these strikers which is in use as a shooting pistol, you will see how well it functions as a trap for grease and residue. This, along with the absence of any exhaust channel within the breechblock itself, mitigates against its purpose as a vent for overpressure. The small hole drilled in the bottom of many Finnish breechblocks, uncovered when the striker is pressed to the rear, would function very well as a pressure release.

I have examined damage such as that pictured by tenbears, above. In the examples I have seen, the fractures do not extend through to the relieved breechblock face, suggesting that escaping breech pressure is not the culprit. As a WAG, I wonder if it might rather be a result of impact fracture of the breechblock against the barrel/receiver face?

--Dwight

[lugerholsterrepair]

Dwight, Dosen't the 9MM round headspace on the case mouth and the step in the chamber is necessary for this purpose if no other?

above. In the examples I have seen, the fractures do not extend through to the relieved breechblock face, suggesting that escaping breech pressure is not the culprit. As a WAG, I wonder if it might rather be a result of impact fracture of the breechblock against the barrel/receiver face?

It could be that this bolt damage was the result of the weapon fireing out of battery, split the unsupported cartridge and the high pressure escaped upwards taking a portion of the bolt face with it?

Jerry Burney

[alvin]

It's great to know my initial view on this still being valid (see my post on the "4th floor") .... my sixth sense works most of time

[Dwight Gruber]

Jerry,

The 9mm cartridge does, indeed, headspace on the case mouth.

Recall, that the 9x19mm Parabellum cartridge case is straight-sided, but tapered. The blueprints for the P08 show that the chamber is cylinder-bored (the diameter of the cartridge base) for roughly 2/3 of its length, that is, to the step. The step is the actual diameter of the case at that point, and follows its taper from there to the end of the chamber, where it headspaces.

Frankly, as a practical matter, I would suspect that the pressure of an out-of-battery, split case would blow out the extractor rather than fracture the bolt face.

--Dwight

[lugerholsterrepair]

Dwight..Yes of course. I was just thinking the bolt has an overlaping edge and one possibility is pressure grabbing it on the way out and with the channel for the extractor...It might be possible to account for the damage shown. On a practical side though, the extractor is pretty vulnarable there...
Whenever I have had a cartridge case blowout on the range it has taken out the magazine as that seems to be the path of least resistance although brass was sprayed into the face of the shooter...Good thing he had on shooting glasses!

Jerry Burney

[Mauser George]

Dwight:

I checked my 1939, 1941 Lugers that are close by and not in my safe and neither have the smaller ID as I described on the early DWM Lugers.

Do you own K-1942 Mauser Lugers that have this smaller ID in the chamber? If so I would be interested to know their date?

George

[Dwight Gruber]

George,

At the moment I have only Imperial-era Lugers. For several years I shot a 1936 S/42 code Mauser, which did have the chamber step.

--Dwight