UPDATE:

I ordered and old "new stock" breech bolt that arrived in perfect condition. I swapped the breech out and put the firing pin and extractor from the original into the new block. The pistol will now cycle a new round with no problems (this was done manually and I did not fire the pistol). The next process was to check the headspace which is the current problem. I called all 3 gunsmiths where I live and they only do headspace work on bolt action rifles.

One of the three told me to pull the firing pin and extractor then use masking tape one layer at a time to see if the round would feed while slowly letting the toggle down. In short I ended up having to add 5 layers before the breech will not close when letting off the toggle slowly so the round is not being slammed in place. I used my calipers and the thickness of the 5 layers is 0.017. I found the following on a google search which took me to "LUGERFORUMS" and it stated the following "minimum headspace measurement from a SAAMI chart is 0.754" and the maximum headspace is 0.776", or 0.022" difference."

My question is using the factory round and having to add 0.017 before the shell would stop means I should be at 0.771 or slightly less which would put me under 0.776? If this is correct I should be within specifications to shoot factory loads?

Thanks,

The only way to actually check headspace in with the correct gauges. A cartridge is an unknown dimension, compared to a gauge. Tape is not an accurate way to gauge headspace. Bad idea. I would not take my firearm to said "gunsmith" for any work.

No one around here want's to touch a 105 year old Luger. As you can see I live in central Wyoming and we have a lot of "custom rifle builders" along with a few older guys that work on revolvers and old lever action Winchesters. I have yet to see an all around smith
which of course concerns me.

you might be closer than you think?
 

A normal commercial 9MM brass case runs approx. .010" under the "GO" or minimum, so you .017"+ addition puts you right about in the middle of the range?... Make sure you check your first shot, and maybe a few more for primer damage/... best, til....lat'r...GT:jumper:

checking headspace
 

BTW, Allen, send the top half complete to me, I'll check it for you, no problem, no charge.... best, GT

gunbugs, you may be a little harsh on the gunsmith. He probably has guages but will not loan them out. He just gave a suggestion on how Allen can make a rough check himself.
Much like the suggestion on the to use masking tape for excessive toggle slap
http://forum.lugerforum.com/showthre...le+slap&page=2

Unscientific, not an accurate measure, but gives one an idea whether there is a problem or not
In this case Allen's gun is on the edge and worth paying to have the headspace measured

Thank you for all of the comments and especially to G.T. for his generous offer. I decided to try one last procedure and I think this the best so far short of an actual gauge. I took a piece of spent brass, removed the primer and put it through the sizer in my loading die then measured the case length at 0.747 and chambered it no issue. I then added a trimmed tape disc up until the bolt would not close with a light steady pressure. I measured the casing with the tape disk on it that would not allow it to go into battery with the noted light pressure and the length is 0.768. I also measured the factory loaded case I used prior and as G.T. stated it was exactly 0.744 which puts it .010 under the standard of 0.754. So I would think at 0.768 with the case not going into battery I should be within the "SAAMI chart is 0.754" and the maximum headspace is 0.776", or 0.022" difference."

Hi Allen,
You are on the right track. If your measurements are accurate, a headspace of 0.768" is well within the SAAMI range, although a little over the CIP standard. Regardless, the pistol should be safe to test fire and then examine the fired cases for any problem. If there is an issue, I'd recommend you send the gun to GT for a close inspection.
Use of tape discs on a sized case head is an acceptable method of checking headspace, if the accuracy limitations are understood. I regularly use this method for obsolete calibres where any standard gauges are unavailable.
Mark

Allen, a free check by G.T. could save you lots of problems later. I believe you can send it priority mail

Unless I'm mistaken, only if you're an FFL holder. USPS regs make us plebeians use UPS or FedEx overnight at around $80.

The frame is the gun. The upper assembly - barrel, receiver & toggle system - can be legally mailed without an FFL.

Actual gauges are not that expensive, compared to any Luger. They can be had at reasonable prices, here,https://www.brownells.com/gunsmith-t...9%2bmm%2bLuger

I think "gunbugs" is right on this. I paid $1,000 for the pistol along with $65.00 for the new breech block and planned on shooting it. By the time I pay to mail it both ways insurance, etc. I could order a "no go" gauge which is all I think I need at this point to confirm I don't have too much headspace.

Thanks again for all of the help on this project!

not true in all cases check ATF regulations - in some cases the upper receiver is the controlled part ! - IE Ruger standard .22 auto + many others - from old atf info booklet -

Barreled receiver can be mailed in one box.
The toggle in a separate box.

I think the reference page shows/states that later on.

But I agree, just buy a no go gage!

correct - it is stated in attachment to my post that barrel + receiver does does not constitute a firearm , but barrel , receiver , + toggle does - but they can be mailed separately + be legal -

Mail it to GT.. Get a gauge if you want it going forward, but a full professional check is well worth the USPS postage, two small flat rate priority mail boxes.

So, the way I see it, past "how do we fix it"...Begs the question,"what is the cause of the failure". Obviously, the extractor tried to beat its way through the slots in the breech block. Why?.... I can see a ruptured cartridge, or some other ammo failure trying to blow the extractor out of the top of the block, but our O.P. says the ammo functioned normally, and the brass looks good. I can't see the parts being so badly fitted by the boys at Erfurt that they sent out a pistol doomed to failure. It seems to me that the little "ears" on the extractor were being forced up into contact with the cuts in the block, and some type of overtravel situation occurred. But, it again begs the question, What is the cause? Too long of a hook on the extractor? Abnormally large diameter rims on the cartridge? What was forcing the extractor up so hard? A weak extractor spring, allowing the extractor to flail upwards without resistance? Without knowing the cause, we may not be fixing anything.

gunbugs,

I think you might be on to something with this statment "Abnormally large diameter rims on the cartridge?"

I have a S&W model 1917 that shoots .45 ACP utlizing moon clips. Normally I shot WWB or RGB ammo out of it. Went shooting one day and Wally world was out of the normal ammo so I bought some Blazer brass.

It was noticablly harder to snap this ammo into the moon clips, to the point that I decided it was not worth the effort. The only reason I could think of that would make the Blaser harder to load into the clips was if the extractor groove diameter was at the upper limits. It did shot fine through my Colt WWI reissue though.

I wonder if the Blazer 9mm cases are manufactured towards the upper limits like their .45 is? Might be worth breaking out the calipers to measure the groove and rim diameters on the case to find out if this could have been a contributing factor to the BB failure.

G57

breaking the block!
 

When a primer is pierced, the rapid occurrence of breechblock damage is from one thing only, and that is escaping high pressure gas going back, and going up! One has to remember, the breech is locked during the first few milliseconds after firing. The only mechanical movement is inertially back, with the complete top end involved, the damage is most likely done before the receiver ever even starts to move... I have seen this progression to failure with my own eyes, and three shots is about the max you get... correct the headspace issue, and the problem goes away! I am so paranoid about this that I always make sure the toggle train closes tight on the "GO" gauge, (yes, you need both gauges!) when installing new or old original barrels. Excessive head spacing can be a result, or combination of the following. Breechblock at one end or the other in tolerance, barrel chambered too deep, wear on any or all of the three main toggle train pins. It adds up fast! Good luck to all when shooting a loose gun! :eek:... best to all, til.....lat'r....GT...:jumper:

I understand the operation on the locking/unlocking system on the Luger, and other firearms. However, the O.P. states that no pierced primers were evident in this occurrence. So, that being said, why would the extractor beat its way through the top of the block? Even with a couple thousandths excessive headspace, the cartridge should obturate, and seal the chamber from gas leakage. I deal with firearms that have excessive headspace on a fairly common basis, and the typical symptom is stretched brass, not gas leakage. Even a pierced primer should not leak enough gas to make an extractor try to leave the gun. Again, the O.P. states no pierced primer here.

Gunbugs makes a great point about the OP; unfortunately many do not read or forget the statement of the problem, nor do they read all the subsequent comments.

I still say that for a 100 year old metal part, with unknown history of how many times or with what ammunition it was fired, to fail.

The thin areas that broke out, have "hidden" sharp corners on the underside, a favorite place for fatigue cracks to begin.

With no pierced primers and what is a fairly common failure mode- the cause for the failure will likely never be determined.

I have ordered the "no go gauge" and will start there. The barrel was never changed out as noted all matching serial numbers up to the point of the breech block failure other than possibly the firing pin which I did not check for matching. I did note the firing pin is fluted which indicates the pin itself may have been changed at some point. The theory on the rim size is intriguing as I have an old "Star" 9mm that jams on the Blazer Brass and works flawless on Remington. I have 2 uneducated guesses on what may have caused the problem if that is even a possibility. I came across a factory cartridge one time where the bullet was set probably 1/3 deeper than the rest however, that should not have affected headspace? Needless to say I did not fire the round out of the Glock at the time and I disposed of the round. Is it possible as "Karl" suggested that for whatever reason the mechanism did not go into full battery? If this is the case could the pistol still fire and that be the cause of the problem? There is really not anything else I can think of as the rest of the parts are in good shape. I shoot a WWI DWM all matching that I have however, only on occasion and all I have ever used is Remington ammo with no problems.

failed extractor relief at the breechblock!
 

Hi gunbugs, a quick and easy indicator, for Allen, of what might, or might not have happened would be a quick look at the rear of the breechblock for firing pin and retainer damage at the rear of the block? With the ejector retainer broken out, it is almost certain that the retainer area at the rear of the breechblock is damaged severely as well... If no damage there, then the ejector area failed mechanically with something causing it to exceed it's yield strength??? Best, til....lat'r.....GT...:thumbup:

Oops, you're right! The upper is all that's necessary to send in order to check headspace.

G.T. here are some better photos of the damaged breech block.

Thanks again for all of the follow up from everyone.

Well you sure blew the lips off that one Allen.

https://i.imgur.com/x9PxXk3.jpg https://i.imgur.com/BJgKb6u.png?1

Yep..

see my two posts in this thread from yesterday - complete upper with breech block is considered a firearm because it can be fired like a pen gun + many other controlled devices -


What is a Firearm? The ATF Definition
This is from the ATF
Gun Control Act Definitions

Define: Firearm

Defined Under: 18 U.S.C., § 921(a)(3)

This section is intended to provide basic guidance in understanding firearm terminology.

The term “Firearm” means:

Any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive;



B. The frame or receiver of any such weapon;


C. Any firearm muffler or firearm silencer; or

D. Any destructive device.

Firearm Frame or Receiver

That part of a firearm which provides housing for the hammer, bolt or breechblock, and firing mechanism, and which is usually threaded at its forward portion to receive the barrel, is considered a firearm per 27 CFR § 4red with out grip frame , same as pen guns + other controlled items - - see posted bulletin from GCA 68 -

breechblock damage
 

Hi Allen, it definitely shows some hard recoil, broken rear corner and such, but the firing pin retainment area looks to be unaltered? I would have to say it is most likely that the extractor retainers on the breechblock could well have failed from just a lot of use? Nothing lasts forever, and in the case of Lugers, sometimes for just a little bit? Good luck with your "NO GO" gauge and testing, I'm still here if you need any assistance that i might render?.... Best to you, til....lat'r....GT :cheers:

Thank you G.T. your help has been much appreciated. I will try the gauge first then a test shot and check the case/primer. If no go it will be on the way to you. I have a couple of P-38's and old Hi-Power and another Luger I have never checked so the $30.00 gauge will get some other use.

gauges
 

Hi Allen, at least with the forum help, you have a lot more info than when you started! :eek:.... As for the gauges, once you have the "NO GO" you can use it as a base guide dimensionally and put scotch tape on the back of a regular empty and make your own "GO" gauge! I've done it many times, and even made incremental sets to see just where I was at when re-barreling?.. I pay a'lot of attention to where the toggle knob is in relation to the receiver rail when using gauges, both "GO" & "NO GO" on closing. You'll get a feel for the exactly right head spacing, more importantly, you'll have a baseline if ever a problem should arise... If possible, I like the action to close tightly on the "GO" .... seems to work out fine in the overall picture.... best to you Allen, til....lat'r.....GT...:cheers:

Thank you everyone for all of the guidance and comments! I will post back how it all works out in the next few weeks. The forum members here are so helpful and knowledgeable. I wouldn't have stood much of a chance without them and I have learned so much about the Luger pistol and the parts that make it work.

Is that pitting corrosion around the axle pin engagement hole? Also some galling?

That would indicate moisture got inside the breech block and toggle train. Corrosion could generally weaken the entire block, as well as retard unlock and cycling by resisting rotation around the axle pin.

While the firing pin hole looks considerably enlarged (more possible evidence of corrosion inside the block), if there were no pierced primers the only path possible for high pressure exhaust gases is around the case, past the oblation ring and back into the face of the breech block before it unlocks and extracts.

That would imply that the cartridge might not be against the chamber case stop ring. Is the interior of the chamber pitted? Is there forward / rearward play in the toggle train?

Would resistance caused by friction and pitting at the breech block axle delay extraction enough to allow the blowback around the case into the breech block?

The "go" and "nogo" headspace gauges are useful when cutting a barrel's chamber, but you need a "field" gauge to verify that you don't have excessive headspace.

Update:

I received the "Clymer No Go" gauge, pulled the firing pin and extractor from the pistol then inserted the gauge and let off slowly on the toggle until it stopped. I then checked to see if the pistol was in battery and it was not. I applied some pressure and it would not budge. There is no question that I do not have too much headspace. I then used a sized, de-primed factory casing and added layers of tape until it would just close with no added pressure required. I measured the case at 0.764 and as noted the Clymer gauge would not lock down or go into battery even with some moderate pressure no movement. So based on the Sammi headspace being 0.754 with up to 0.22 allowance for a max of 0.776 I should be good to go on a test fire?

The more I looked at the breech and where it failed up close there appears to be almost small bubbles in the metal or more what one would see in "pot metal" or cast iron. I think as many have said the failure may have been just due to age and wear. The only issue I could see now is if for some reason the firing pin pushes through too far on a primer? The rest of the parts are all in excellent shape and the replaced "old stock" breech block looks to be new other than the number does not match.

...

I sized a piece of brass, inserted a primer and test fired the empty casing to make sure the primer strike looked good. I inspected the primer after firing and it was right on the money, not too deep and not too light. I think we are ready for a test fire!

we are waiting Allen :-)

Hoping to try it out this weekend. Two weeks plus of below zero weather, snow and wind gusts of up to 80 mph before and after.

I just returned from the range after completing all of the prior noted. The pistol functioned flawless through 2 magazines with no issues. Thanks again to everyone for all of your help!