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Unread 10-29-2020, 04:53 PM   #21
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Quote:
Originally Posted by DonVoigt View Post
Sprangy,
That is not the original or intended purpose of the grooves, they are there to collect gunk, dirt, trash and allow the striker to still function.
It is however often repeated "common knowledge" that is just not accurate.

This subject has been the focus of several threads, but if one simply observes the location and extent of the grooves, it is clear that there is nowhere for any trapped gas to go, even with the striker to its full rear position.
Don, while Gortz & Sturgess acknowledge that the flutes had the primary purpose of allowing oil and dirt to flow past the firing pin to prevent build up of residue that reduced the impact force of the firing pin, they also point out that the flutes do, in fact, allow gasses from a punctured primer to bleed off and reduce the rearward thrust of the firing pin that would otherwise cause damage if the firing pin was not fluted. G&S point out that it is a benefit but, as you state, not the purpose for which the flutes were intended. G&S red books, pages 1115 & 1116.
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Unread 10-29-2020, 05:53 PM   #22
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Quote:
Originally Posted by DonVoigt View Post
Sprangy,
That is not the original or intended purpose of the grooves, they are there to collect gunk, dirt, trash and allow the striker to still function.
It is however often repeated "common knowledge" that is just not accurate.
Thanks DV & Doubs ... you know I knew that ... I have read exactly what you said elsewhere but sometimes my 70 year old brain misfires and I don't always remember These days I often can't remember anything past the last 24 Hrs. ... a combination of old age and the drugs I have to take for chronic pain.

John Walter (The Luger Book p.116) notes that the fluted firing pin was patented by Georg Luger as early as 1893 (DRP 78,406; DRP 90,433) as a method to keep striker-chambers clear of fouling.

Also as we are talking about a 1940 P08 Army Mauser its my understanding that it would have been manufactured with a fluted firing pin anyway as the fluted design was instituted in 1934. Having said that we can't know that the firing pin may have been replaced with a non fluted design in some other repair cycle.

so much to know ... so little time.
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Unread 10-29-2020, 06:58 PM   #23
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This post references two Luger firing pin patents: (DRP 78,406; DRP 90,433)

Both German patents are assigned to Georg Luger.

The second patent discusses bypassing gasses. This is a google translation of the first paragraphs of the patent:

"The present invention relates to further embodiment of the gas paths protected by D.R.P. No. 78406, which are used to reduce hazard and counteract the effects of the explosive gases which repel the impact bolts when the latter is caused by shocks as a result of damaged ammunition and the like enter the chamber.

The new facilities are intended to cause the gases, which have penetrated, to flow as freely and rapidly as possible through the gas passages behind the Plate of the impact bolt and into the interior of the chamber. For this purpose, either the plate of the striker is dimension-ed such that between it and the bore of the chamber, a corresponding clearance is formed as a gas path, or is formed on the inner wall of the chamber When the striking pin is bent, whose plate is surrounded, or otherwise any suitable recesses are arranged for the same purpose.

These grooves or recesses can be used alone or in combination with the other gas paths of the impact bolt."

Click on the patent number (above) for a PDF of each patent straight from the German patent registration site. It's a wonderful resource for researching things firearm in Germany. I used it to great impact when working with Mauro and Gerben on the Mauser book recently published.
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Unread 10-29-2020, 07:28 PM   #24
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Nice ... Thanks for that mrerick
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Unread 10-31-2020, 11:20 PM   #25
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Quote:
Originally Posted by Doubs View Post
Don, while Gortz & Sturgess acknowledge that the flutes had the primary purpose of allowing oil and dirt to flow past the firing pin to prevent build up of residue that reduced the impact force of the firing pin, they also point out that the flutes do, in fact, allow gasses from a punctured primer to bleed off and reduce the rearward thrust of the firing pin that would otherwise cause damage if the firing pin was not fluted. G&S point out that it is a benefit but, as you state, not the purpose for which the flutes were intended. G&S red books, pages 1115 & 1116.
Doubs,
I know G&S "say" that, but it is a physical impossibility.
"They" got that statement wrong; it just is not physically possible, there is no where for the gas to escape to!

Marc,
The reference to the fluted, or gapped alignment disc shown in the drawing for the rifle bolt is an entirely different situation, and those channels do lead to an "expansion" area and eventually to the outside of the bolt.

Carefully observe the length of the grooves in the luger striker, and how far they extend, and find where the closest gas "escape" route is- the two do not intersect.
There is a slight possibility that some grooves cut by hand, when an old style striker was modified to include the grooves, "Might" be cut deep enough, and long enough, and in the correct alignment with the sear tab opening to "connect" just a bit-
But that condition is only met if all three requirements were met by accident !

Such a co-incidence was not intended and is not observed in machine/jigged production strikers.

I know the presence of the grooves just begs for the answer to be "gas management", but it just is not so.

Just an addition note, the Finns added a "real" gas escape hole in the bottom of their breech blocks, that hole is far enough forward to allow gas to escape.
Swiss strikers have a flat milled into the front and rear bearing surfaces of the striker to allow gas to pass along the length of the striker and exit the breech block.

Both of these later techniques/modifications do serve to allow gas to escape from the front of the striker in event of a pierced primer.

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Unread 11-01-2020, 10:31 AM   #26
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At a minimum get a new breechblock from G.T. Also, never test a Luger's action with live rounds as you apparently did before Don's advice. I have had two Lugers that fired after releasing the toggle- luckily at the range and pointed downrange. That was no fun, but in one's house could be tragic!
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Unread 11-01-2020, 05:32 PM   #27
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Quote:
Originally Posted by DonVoigt View Post
Doubs, I know G&S "say" that, but it is a physical impossibility. "They" got that statement wrong; it just is not physically possible, there is no where for the gas to escape to!

Don, I understand. It's somewhat surprising that the flutes weren't extended past the collar to allow gases from a ruptured primer to escape. I've actually had a FP keeper shear the small lug off when a primer ruptured. I've often wondered if the keeper was made of softer metal for that very purpose.

I also once owned a Finnish M23 that had been modified with a hole in the breechblock to allow gas to escape. A logical and good idea IMO.
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Unread 11-01-2020, 08:38 PM   #28
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Hi All,

I agree with Don's comments and illustrations completely.

If memory serves, Vlim also agreed with us, several months ago, on this exact issue.

Those Finnish master gunsmiths certainly knew what they were doing!!

Luger may have been issued the D.R.P.s, but were they for a Mauser Rifle bolt firing pin design originally; as, strangely enough, Georg Luger managed to have D.R.P.s issued to him on several of Paul Mauser's original rifle designs!

Respectfully,


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Unread 11-02-2020, 05:56 AM   #29
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Quote:
Originally Posted by DonVoigt View Post
Doubs,
I know G&S "say" that, but it is a physical impossibility.
"They" got that statement wrong; it just is not physically possible, there is no where for the gas to escape to!
I'm sorry to say but I don't agree with you. There is indeed a way for the gas to escape. It's from the side cut of the breech block.



Mind you that you only need to relief enough pressure to prevent the firing pin to act as a piston and go full force backwards. And you know what? It works.
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Unread 11-02-2020, 10:51 AM   #30
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Kurusu,
That is the nearest spot/point for gas to escape, for sure.

A portion of gas can escape around the gap between any style striker and the breech block; but not due to the presence of the fluting cuts - but due to the normal tolerance between the two parts.

As I wrote, some cuts could be long enough/deep enough and could function that way.

Retract the pin all the way and see if you can see the flutes; most of the time one can't, but occasionally a groove does reach that point.

My basic point is that gas relief is not the primary reason or intended purpose for the flutes-which is to provide a place for grease/oil/debris etc- and keep the striker functioning; if they relieve gas it is serendipity at work. JMHO.

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Unread 11-02-2020, 11:31 AM   #31
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Quote:
Originally Posted by DonVoigt View Post
Kurusu,
That is the nearest spot/point for gas to escape, for sure.

A portion of gas can escape around the gap between any style striker and the breech block; but not due to the presence of the fluting cuts - but due to the normal tolerance between the two parts.
The basic problem with the "old fashion" firing pin is that oil( if present) will fill that gap and act as a seal.


Quote:
Originally Posted by DonVoigt View Post
As I wrote, some cuts could be long enough/deep enough and could function that way.

Retract the pin all the way and see if you can see the flutes; most of the time one can't, but occasionally a groove does reach that point.
You don't really need to see the flutes. There are to diameters in a fluted firing pin. the flute go all the way to the "narrow" portion.





Quote:
Originally Posted by DonVoigt View Post
My basic point is that gas relief is not the primary reason or intended purpose for the flutes-which is to provide a place for grease/oil/debris etc- and keep the striker functioning; if they relieve gas it is serendipity at work. JMHO.

I really do not know what was the primary reason. But I know it works.

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Unread 11-02-2020, 07:18 PM   #32
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Quote:
Originally Posted by kurusu View Post
The basic problem with the "old fashion" firing pin is that oil( if present) will fill that gap and act as a seal.




You don't really need to see the flutes. There are to diameters in a fluted firing pin. the flute go all the way to the "narrow" portion.







I really do not know what was the primary reason. But I know it works.

Hi,

Don's contention is correct.

Sorry, but fluted or not, a pierced primer will, indeed, cause enough "piston effect" to damage the firing pin retainer or the grooves cut for it in the breach-block itself. This is the reason for most Luger mechanical failures.

This has been my actual, verified, experience gentlemen.


Respectfully,


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Unread 11-02-2020, 10:06 PM   #33
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Default pressure relief

Hi to all, although rare, I have had a few encounters with both over pressure, and pierced primer gas leaks with lugers, which occurred over the last 20 plus years when GT Specialties really started to ramp up luger repairs!! First the firing pin gas relief issue. I have had several pierced primers both due to excessive headspace, and/or a corroded firing pin tip. A famous pro football coach once called a ref over to his sideline during the game and said to him, "do you know what NFL stands for?" he quickly followed it up with, "not for long, for you or me you keep making calls like that!"
The same holds true with the pierced primer / gas relief... Regardless of the pin style, you have approximately 2 or 3 more round to shoot, and all is going to give up into a big pile of useless gun parts! First, the breechblock extractor supports on either side of the extractor lift, then very shortly after, the firing pin drives the retainer out the back of the breechblock, and with that, game over? Now, too stiff of a load, causes other failures, I have had broken receiver pins and also broken (in half) firing pins... plus it just beats a probably already beat luger to death... On every range trip (with different guns!) I check the primer on the first shot... it can tell you a lot, and save you a lot as well.... best to all, til.....lat'r....GT
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Unread 11-02-2020, 10:24 PM   #34
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Excellent advice GT ... from now on i will take a good look at my fired 1st round brass for a pierced primer or any other sign of trouble and examine all at end of my session.
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Unread 12-17-2021, 02:51 AM   #35
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Well, I am hard headed, but I have to admit when I am beat. Since my last post, I went out and bought a second Luger P-08 to better understand the gun and what was correct.

So the gun with the issue I will refer to at 1940.
And the new one is 1916.

I am gaining an appreciation to the old armorers and the new guys working on these hand fit guns today. GTI think this gun will need to go to you, but I am not sure if the lower needs to go also.

The breach is not correct. Not sure if issue.
Extractor doesn't look correct. Not sure if issue.
The bullet ramp on the lower and the feed ramp on the barrel. The lower has had material removed. The barrel has not. I am guessing this is where my real problem is. This is beyond my skill set.

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Unread 12-17-2021, 02:57 PM   #36
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Default feed ramp mod?

Hi RWBlue01, from the chamber pictures you show, the problem could indeed be the feed ramp cut on the barrel chamber lip? The frame looks fine to me, and I think we could do the barrel first and go from there? I could modify the ramp to the correct angle and length and range test it on one of my test frames to insure proper function? My mailing address is:

Gerald L. Tomek
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Chandler, AZ 85225 - 7117

Best to you and yours, til.....lat'r.....GT...
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Unread 12-17-2021, 04:44 PM   #37
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Do you want the complete gun or just the upper at this time?

Thanks,
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Unread 12-17-2021, 05:06 PM   #38
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Default just the upper

If I revise it and it works on my frames, it will be good, and if any problem still exsists, it is most likely that the upper will not be the fault...Just the complete upper for now.... best, til....lat'r.....GT...
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Unread 12-17-2021, 05:23 PM   #39
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Default lined?

From the picture, it almost looks like a relined barrel sleeve? either way, it can be corrected... best, GT
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Unread 12-17-2021, 10:27 PM   #40
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Have you tried the 1916 to see if it feeds ok? Fired it?

If the 1916 feeds ball ammo, it does not need any work on the barrel ramp.
Barrel ramps are only cut into the barrel, and not into the upper receiver.

The pictures below show a 9mm barrel with its ramp on top;
the next three show three stages in lining a barrel to .30 caliber.
The top picture shows the barrel liner in place, the second shows the .30 luger chamber reamed, and the third shows the finished ramp blended into the original barrel.

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