Breech block extractor problem
 

Hi guys, I went to the range today and put about 30 or 40 rounds through my Luger. It was standard Federal 9mm Luger ammo.

I started to notice the metal at the top of the breech block started bulgeing from the keeper steps of the extractor:

http://i.imgur.com/kMD5N6a.jpg?1

What is causing this? Is it a headspace problem? Because I know I am about at the max headspace (.776)

Thanks for your help.

Is it a Erfurt? I had a breechblock do exactly the same thing in the same place. Don't know if excessive headspace would cause it or not. On most lugers, there is a gap when closed between the breechblock and the face of the reciever, so I don't think a deep chamber would make the two parts slam into each other.

What is the condition of the rear of the receiver between the ears where the rear toggle hits is? Is it getting hammered or peened?

This could be a weak recoil spring.

Marc

I hsve no idea what causes that deformation but I do know that I have seen several examples of breech blocks that have "spalled" at that location, with pieces actually missing from the front of the block. It looks like this breech block is headed in that direction...too bad.

A couple of questions....is this an original breechblock or an aftermarket item? Does the extractor move freely up and down in the extractor channel?

I agree with Ron. We are seeing the "before" photo of that typical double chip breechblock that gets presented on occasion.

I think it is a DWM.

It is an orginal breechblock that I bought from the Luger Doctor a year or two ago. The extractor moved freely.

It dosen't look too bad. (I think) here are some pics:
http://i.imgur.com/YWhYn9m.jpg?1
http://i.imgur.com/DjQ1VTZ.jpg?1
http://i.imgur.com/FjGYDm7.jpg?1
http://i.imgur.com/4PU7ZVO.jpg?1

I just wonder because of the headspace, when the round fires that the case dosen't have a good seal in the chamber and the casing is ejected sooner than it should be. Like timing is off, I don't know.

The headspaceing always did bother me, I should probely try fixing this first. This will be tough because I have to somehow turn (screw in) the barrel one whole revolution. And then recut the chamber with a chamber reamer (which I do not have).

I don't think you will have success with your idea of setting back the barrel, there won't be enough of the flange left; the extractor cut would have to be re-done, in addition to re-cutting the chamber.

What you need is a different bolt, or front toggle if the head space closes on a "field" guage.

Looking at the picture, though it may be a shadow or the angle, is the extractor broken? Allowing too much movement.

Have you had the extractor out to see its condition?

What ammo are you shooting?

How did you arrive at .776 as the headspace?

You are right, moving my barrel one revolution would require approximately.050 of stock removal. (I just checked it.) So that is not an option. Yes I have had extractor out and no the extractor is not broken.

I made a brass plug exactly.776 in length slightly smaller than the diameter of the chamber. The toggle with breechblock will close and lock on it. You can feel it touch the chamber lip edge and breechblock face. It hardly takes any force at all to lock the toggle, but it won't close in a free state.

I was shooting Federal 9mm Luger ammo.

I wonder if it's possible to sleeve toggle hole which pins to receiver. If I moved it about .015 that would give me a headspace of .761

Min is .754
Max is .776
The mean would be .765

It would be a major operation to mill/bore a hole offset to the front, in an existing block; and that would not solve the existing problem of the damaged area.

You need a new block and may have to select fit from more than one to reduce your headspace- though I do NOT think headspace is causing this problem.

If you felt any resistance on the closure on your guage, the head space was shorter than the guage. The brass is likely now deformed, guages are made from steel for just this reason.
Closing the toggle with any force negates the use of the guage, as the toggle gives additional leverage.

My no go guage is 0.757 and the go gage is 0.751 (just measured them), so there is something amiss in the land of guages and measurements it seems.

Where does your data on headspace come from?

What I see is more in like with the brass measurement mentioned of 0.745.

Cartridges of the World gives a case length of 0.754.

I did find this SAAMI spec page, which gives the head space from
.754 min to .776 max. As we know, military specs will be different, usually larger.

I guess an easy thing to do would be to change the main spring and see what happens.

I just wonder if it is the timing, toggle is blowing back too soon.

When you have the complete toggle train out of the receiver, are the joints/pins a good fit with minimal side to side, and fore and aft movement? The headspacing on some of these old warhorses is pretty "generous" but not producing that kind of result to the breechblock. Is your extractor OEM or aftermarket?

The pins and joints are bit worn but not terribly.

The extractor is a aftermarket. With aftermarket spring.

The pistol shot very well no feeding problems and no ejection problems and was very accurate.

I gotta get it running right, it is so much fun to shoot.

Vic,

You say above that is shoots well and is accurate, what are you tying to get running right? Sounds like it is, the breech block has failed
in a minor way, but still works.

IMO, until you get the front end "fixed", everything else is really secondary.
The bolt is damaged and needs to be replaced, it won't get any better or heal itself-JMHO.

Of course if you are happy with the appearance and possibility of greater damage you can just shoot it as it.

Before you change the spring, count the coil turns and report.

Vic,

I have to lean toward a faulty breechblock from a metallurgy standpoint(possibly a heat treatment issue). I am at a loss as to what else could cause this. There is a very strong chance that with this condition, and continued firing, that the two elevated areas on each side of the extractor channel will break off. There is a photo of a breechblock doing this very thing on this forum.....I can't remember exactly where I saw it. I really wish that I could be more help to you. :(

While several of us have seen breechblock chipped in this area before, I would have to opine that history doesn't necessarily repeat itself, and since this appears to be a heat treatment/hardening issue, I would NOT recommend continuing to shoot with this breechblock, because there is no way to predict how this particular part may fail. An unexpected failure could be catastrophic and cause injury...

Please replace your breechblock before shooting this weapon again. Just my $0.02, but I recommend you spend it wisely, instead of with hindsight regret...:cheers:

IMHO

I believe that we have been looking at this from the wrong direction. The extractor is retainer in the breech block by a pivot pin and two small flanges on each side of the breech block slot. When fired the recoil drives the cartridge case into the ejector. The ejector rotates the cartridge around the end of the breech block face pushing against the extractor. The extractor is then driven into the small internal flanges in the breech block slot.

After looking closely at the functional aspects of the breech block mechanism, I believe that there are at least two possible causes for this spalling problem

Possible insufficient clearance between breech block slot internal flanges and the extractor. Improperly fitting of the extractor, breech block and the ejector.

If the cartridge case rim is too thick upon ejection the extractor is forced into the breech block slot internal flanges. Possibly the breech block internal flanges are not thick enough for this type of forced loading.

Whatever the cause, the breech block needs to be replaced for safe use of this pistol

That's my 2 cents.

My take on this is that the extractor must be pounding the insides of its slot laterally--in both directions-- in order to displace material up like this. Unfortunately, there's no discernible way--to me, anyway--for this to happen. The pic shows extra space, both behind the extractor's ears and its tail. One possibility is that, if it's a repro breech block, the slot profile was cut too far back, though how this setup could pound things sideways, as I said, is beyond me at this point!

You are right John, I do not plan on shooting it until I get a new breechblock. When you look at the breechblock face where the keeper steps for the extractor are with a magnifying glass you can see a small fracture. I don't think I would look very good with that embedded in my face....lol.

I have ordered a new reproduction breechblock and extractor spring. Also I ordered a recoil calibration set from Wolff. It says it comes with 3 mainsprings a 36, 38, and 40 lbs mainspring. I can experiment with these.

The thing that really bothers me is my headspace issue. If it is true (and I believe it is) DonVoigt said he measured his go/nogo gauges and they were .751/.757 My headspace right now is .776!! My chamber is cut wayyyyy too deep by almost .020 That's bad.

I thought I was ok because I was going by the SAMMI spec which said "min .754, max .776".

I bought this reproduction brand new barrel from Numerichs. It is a very nice well made barrel, they just messed up and cut the chamber too deep.

I really like the barrel and wish I could save it, but I don't think I can. Cause I like the idea of having a brand new barrel. I want a good shooter for a long time.

So now I got to try to find a new old (in good condition) 4 inch 9mm barrel that won't break the bank.

Dick, I made very sure that the extractor fit into the breechblock and extractor clearance slot in the barrel and receiver, I am a tool and die maker by trade.

As you know, when a cartridge is in place the extractor pivots about the small retainer pin. The extractor retains the cartridge and projects above the breech block. The extractor moves vertically toward the breech block internal flanges for retention and alignment. The ejector pushes the cartridge and the extractor vertically upward. If there is forceful contact made with the small breech block internal flanges a cantilever load is applied. The vertically applied load causes a bending moment reaction to roll the internal flanges into the damage displayed on the photo.
IMHO

The way you describe it makes total sense. Do you think the blow back has to much force causing this to happen? Because I believe I have good clearance on everything. Which would point to a worn main spring.

It's almost like using +P ammo, but I am not. I am shooting standard ammo.

I have observed that the cartridge retainer finger section of the extractor should be completely clear of the breech block end cartridge counter bore when the cartridge is released. At that point there should be additional clearance before the extractor engages the small inner flanges of the breech block.

However, if the clearance of the extractor to breech block is insufficient or the ejector is too long, either situation might be forcing the extractor vertically into the inner breech block restraint flanges.

I suppose that if the loads are too hot the increased recoil could contribute to this damage. You did state that the cartridges were standard Federal 9mm Luger ammo. Is that a hot load?

We have more in common than Lugers, I served my Apprenticeship as a Tool Maker before going back to college to become a Mechanical Engineer.

Vic,
replace the breech block before you decide the barrel is bad or cut too deep.
The block is the other part of the headspace equation, and a longer block will reduce the head space..

The Guages I measured are the go, and no go guages. There is a third-the "field" guage which is longer(I have not been able to find out how long) and is the one used to determine when repair is needed.

When you described measuring your head space, you did not have .776 as you "felt" resistance, but then kept pushing, so your head space IS below the max.

I would try again with a steel guage and do not use any force, of course the striker and it's spring must be removed for the test.

Even if it were slightly above the max, I do not think this is the problem or even part of the problem you see.

And don't forget, military specs and European specs are quite likely different than SAAMI specs.

Folks tend to worry about head space more than necessary, even to the point of obsession; within reason, head space only affects accuracy and the surety of ignition.:soapbox:

One of my favorite pictures is one of a short rifle cartridge fired in a long chamber, head space of about 1/4" and the only noticable
result of the firing was the odd brass that was ejected! This was caused by a re-chambered rifle that was not marked.

Has little to do with Lugers, but a lot to say about head space.

Well... I got my order from Numerichs.

The breechblock was nice, hardly any fitting. Got a couple extractor springs, and a mainspring.

The mainspring can't be right, there is no way that spring would fit into my shooter. The wire diameter is.055, it has 22 coils, but it's like 4.200 long?!?

What the heck?:
http://i.imgur.com/j6sVGKE.jpg?1

Breechblock looks and works good (by hand):

http://i.imgur.com/aFJhurr.jpg?1
http://i.imgur.com/t37x9TG.jpg?1
http://i.imgur.com/9TKIXo2.jpg?1
http://i.imgur.com/CDEVWKD.jpg?1
http://i.imgur.com/DqdCdpp.jpg?1

I did order the mainspring set from Wolff, and I am still waiting on those. Oh yeah, my mainspring seem very stiff. The wire measured .055 diameter, it had 21 coils (looks like someone cut or ground one end of it. I forget the length it measured, but it was close to what the chart said that I saw in the sticky thread in this forum. To me my mainspring seems pretty good by the way the pistol feeds and ejects.

If these changes do not correct my problem, I think I will need to correct the headspace (mainly because I have run out of ideas) and that I know is not to spec. And the rest of the pistol seems to be in spec.

So I will be needing a new orginal barrel in good, to very good, to excellent condition, possibly barrel and receiver or whole upper assembly.

My funds are kinda limited right now, I've been pumping a lot of money into my AR's and AK's (wife is ready to flip out....he he)

I kinda hate to do this,but I have an orginal artillery Luger sight that I could barter with. If my breechblock problem dosen't get corrected and I decide I must change out barrels to correct headspace problem

Here are some pics of the artillery rear sight:

http://i.imgur.com/KLiTqFu.jpg?1
http://i.imgur.com/M7uT8se.jpg?1
http://i.imgur.com/n08SOcG.jpg?1
http://i.imgur.com/bnQTWAb.jpg?1
http://i.imgur.com/AvdCGJb.jpg?1
http://i.imgur.com/EQapW29.jpg?1
http://i.imgur.com/orekvKG.jpg?1

barrel work for art sight trade!
 

When you decide what you'd like to do, drop me a note at gctomeks@msn.com I'm always doing crazy stuff like trading work for parts and whatever?...:)...... I can re-barrel and headspace your receiver assembly correctly without too much trouble?....Best to you, til...lat'r....GT....:cheers:

barrels....
 

BTW, if you want the best, look for a Mauser or Steyr WW2 armorers replacement barrel... it will probably index perfectly and headspace correctly as well... next would be any "GERMANY" barrel, followed by any "MADE IN GERMANY" barrel, after that, it is a crap shoot!.... I do have some nice take off barrels, but they are not new?...best to you, til...lat'r....GT.....:cheers:

Hi G.T.
Are you saying that my existing barrel could be corrected? I really like.(it is very well made, looks and matches the pistol's look (blueing wise) and bore is brand new!...just what sombody that wants a shooter needs.

How would you do it? I figure my headspace is about .020 too deep. I would have to spin the barrel one turn which amounts to about .040 or .050 thou. And that is about the thickness of my barrel flange, so round flat area would be gone it would become a sharp edge instead of a flat. Unless you have some trick up your sleeve.

I have pondered this before!
 

And I think that the barrel could be cut / set back one full turn, and at the same time cut (as large a radius as possible?) slightly forward as well? And then a spacer cut and pressed on to replicate the shoulder and flange area, and install and profiled same as the original concave radius and flange? It would be like a two part barrel?.... all it has to do is re-index correctly and tightly, and also have the extractor and feed ramp recut, and be re-chambered to close on the "GO"... I could accomplish that? :) It wouldn't be perfect, but I bet it would work?.... Anyway, some better than .020" too deep on the breech end??...:).. Best to you, til...lat'r....GT .....:cheers:

headspace....
 

Hi Rick, My father was an old time gun shop owner thru the 50's and 60's... I was always anal about headspace, and he always said it's not a big deal???? We never resolved our differences on this matter? .. But, my opinion was, it never hurts to be within spec?.... Miss ya dad!....:)..... best to all, til...lat'r....GT......:cheers:

Rick,
Your analysis of the possible reason for the upset breech block in the OP's pistol is logical and may be the cause for the upset material, along with a "soft" block to start with.

As I have said about this one, several times, he needs a new breech block. This may correct his long head space too. If it does, everyone is happy.

The OP did NOT check his head space correctly as described, and his pistol is not currently out of
specification, it may in fact be several thousandts below max. He used a Brass gage(deformable) and used pressure to close the toggle!
See his post #9 for how he checked head space.

Unfortunately in mechanical devices, min/max specs can add up the wrong way and 0.020 or more gap space or what ever are frequently present.
Given the condition of the bolt, it is tough to accept that just a few rounds did this, maybe a few +P rounds or hundreds of normal rounds; or a breech block that for whatever reason finally failed?

No one is advocating firing the wrong ammo in a wrong chamber, the point of that post is that when it happened, nothing "bad" happened, except to the brass. The chamber Should have been marked when converted, but was not.

Heads space is not a "mere token", it has it's place, but it is way over-emphasized by many, including some who work on these things. Using SAAMI gages to pass or fail military chambers is easy to do, but not correct in many cases.

Vic, needs to check his new parts combination with a steel gage and no excess pressure to close the toggle
see what he has now.

JMHO.

"Nothing happened bad in the rifle deal, got that. Lots to say about the relative strength of the action and its gas handling characteristics. Might not always be that way, so why even approach the issue on trial and error; a basic, simple chamber cast might have prevented such, but in hindsight.................... probably not."

Just to put the rifle example to bed:
The rifle in question was a stock appearing T 38 Arisaka, with no indication that any modifications had been done. The round fired was a 6.5x 50mm Japanese, in what turned out later to be a 6.5 x 57 mm chamber.

The re-chamber to 6.5x 57 or as sometimes called 6.5 x Roberts was not marked, but should have been- and is now.

You were not "out of place" making suggestions, since we see the issue differently it is good
that you say what you think.

As to calling into question the way the OP did his test, he said himself that he used pressure to close the toggle, that it would not close without but stopped at resistance. Closing with pressure and the subsequent leverage effect , in my book, negates the accurate assessment of the measurement. So it took no "gumption" on my part to say it was not done correctly- he said so himself when he described his actions.

Like Forrest Gump said, "that's all I have to say about that".

Damaged breach block
 

After the OP, send me a link to this post.
I want to add my 2 cents.

One aspect of extractor movement is overlooked in everyone's response.

Any combination of case - extractor- breach block connection, will damage the case first, if the case is brass. Examine the cases if possible.

To damage the breach block in such a way by extractor movement , it has to do so by interacting with a metal.

The only metal extractor interacts with , other then breach block is barrel and slide.

I have seen this happen in cases of a barrel extractor clearance hole has been cut short or with a wrong angle,
or barrel twisted out of alignment just to the point where extractor slams in to it.

In any case extractor must found an obstruction on it's way, that has forced it up, without anywhere to go it pulled the breach block weakest point out.

At this point, i recommend, changing the barrel or cutting it back a turn with cutting all back geometry deeper for clearance as part of the rework.

Change the breach block and examining the extractor interaction with all parts , without firing the gun.

and possibly changing it as well, as it must have internal stress from such a damage.

I can do the rework if needed, and i have all the parts in stock.

Hope this helps

I have spacers if needed, not a bad idea.
As long as a chamber not to long already.