An inherited 20's Commercial - too little headspace?

MileMarker81 · 01-30-2010, 11:33 AM

Hello.

I recently inheritied a 20's Commercial from my mother-in-law's estate. It was her father's gun so it has quite the sentimental value.

All the numbers are matching but there is no clip.

My boys (a 17yo and a 20yo Marine) want to shoot it at least once. The Marine will be taking his pre-deployment leave in about 6 six weeks, so I have until then to make sure that it's safe to fire.

I've stripped, cleaned & inspected all parts and there is no obvious wear or cracks. The action is smooth. So far, so good.

I rented a Go/No-go gauge set from an online gunsmith supply shop and the breech fails to fully close on the GO gauge.

To double-check I made sure that everything was clean and checked the gauge demensions against the published SAAMI specs and it all checks out again. Hmmm.

Do firearms lose headspace with age? It seems odd to me. Could this be a matter of old tolerances vs. new tolerances? All of the appropriate Nitro proofs are present so it had to be checked at least once in it's life.

What do you guys think?

Thanks in advance,

Rob

policeluger · 01-30-2010, 12:44 PM

They lose head space with firing, but not by aga alone....was the extractor keeping gage from closing......is this a 30 or 9mm.....and correct period mags are easy to come by.....I would supect the gage.....let us know and welcome here....

mrerick · 01-30-2010, 12:52 PM

Have you inspected the breech and barrel interior for corrosion?

When testing headspace on rifles, you must remove the extractor and firing pin. It may be the same on pistols like the Luger.

Does it look like the barrel was changed out at some point? (Does the barrel serial number match the frame?)

MileMarker81 · 01-30-2010, 01:23 PM

Hi Guys.

It's a .30 cal luger.

I removed the extrator and firing pin when checking with the gauge.

The barrel numbers and frame numbers exactly match and so does the witness mark between the barrel and receiver.

There are two digits under the sight that match the last two digits of the barrel/frame. I have to think that everything is original as it came from the factory.

I can't see any obvious corrosion. There is certainly not anything foreign in it preventing the gauge from fully seating in the chamber. I could try to take some pictures, but the point-and-shoot camera that I have doesn't do well with macro shots.

How do they lose headspace from firing? All of the forces are going the other way (pushing the barrel away from the receiver)and wear would make the headspace bigger not smaller. Maybe this is one of those counterintuitive things but I just don't get it. Anyone know of a good explaination? Every explaination of headspace that I've read so far has said that headspace increases with use.

Thanks again,

Rob

Edward Tinker · 01-30-2010, 01:26 PM

Rob, the standard line is "take it to a gunsmith and let them check it for safety".

With Lugers (and I am no expert on things like this), the barrel and the extractor have to be lined up, so unless you have a mismatched barrel or mismatched or damaged breechblock, then its hard toget out of whack.

I have never tried a no/no go gauge on any luger I have fired, although I'm more of a collector than a shooter anymore.

Ed

policeluger · 01-30-2010, 05:25 PM

Firing does over time wear the chamber and bolt face, causing excess head space over time....when checking HS did you take the top off the luger so as to have little outside interferance, would you like to set up a time for a phone call.....I hate the key board.....maybe we can figer this out one to one......

LugerVern · 01-30-2010, 09:19 PM

Georg Luger developed the 7.65mm cartridge from earlier 7.65 mm rounds. The 7.65mm Parabellum cartridge uses a shorter cartridge case than the 7.65x25mm Borchardt, 7.63x25mm Mauser, and 7.62x25mm Tokarev cartridges, which are the about same length.

Make sure you are using the right gauge.

Vern

alvin · 01-31-2010, 08:52 AM

If ammo can get in without obvious deformation, but "GO" gauge cannot, most likely it's the wrong set of gauges.

If ammo cannot get in, then .... wrong gun.

===

[Edit] WARNING: This gun can accidentally discharge in disassembled mode. Play at your own risk and know where muzzle points all the time.

policeluger · 01-31-2010, 08:59 AM

Alvin, Milemarker did state in first post that he "miked" the gages to be double sure.....??

MileMarker81 · 01-31-2010, 04:22 PM

Thanks for the input everyone.

I've called ten gunsmiths in a 30 mile radius of my house and no one has the tools on hand to check headspace for this pistol. I will keep trying until I find the right gunsmith. No worries, since I'm having problems Ill get it checked out.

About the gages that I'm using, they are rented from Elk Ridge Reamer Rentals. This is a company that specializes in renting tools to gunsmiths so I have to assume that they are correct. (Imagine the liability of shipping bad gages.) They appear to be milled steel in roughly the shape of a round. The are hand engraved: "30 Luger GO PPG 3.00" and "30 Luger NO.GO PPG 3.00".

I am using page 28 of this as a guide: http://www.saami.org/Publications/205.pdf

These are hard to measure, but distance from the rear of the gage to the beginning of the necks are: (See photo)
GO - 16.32mm
NO GO - 16.59mm

According to the SAAMI document, for a shell this distance is 15.893mm. Is that difference the required headspace?

I don't have any ammo for this. If FedEx is to believed, that will change Tuesday. I have to say though, that I am not comfortable using live ammo to test anything. I have Zoom snap caps for this purpose for the other firearms but am unable to find them in this caliber. I'll see if I can talk a reloader into making me some dummy rounds.

Ron Smith · 01-31-2010, 05:40 PM

Something that you might check, is to see if there's a separated case stuck in the chamber. It's a long shot, but it does happen.

Here's an example. Fired a .30 shooter with a handload that I have used in every .30 that I have owned. The previous round separated ejecting the lower half of the case. The subsequent round jammed itself into the upper half that was still in the chamber. When I finally got the toggle open this came out.

policeluger · 01-31-2010, 07:15 PM

Ron, he did say that all parts were inspected.....I can't wait for the end....

MileMarker81 · 01-31-2010, 09:37 PM

Quote:

Originally Posted by policeluger

.....I can't wait for the end....

Me either.

A couple of gunsmiths that I talked to pointed me to a Gander Mountain about 40 miles from here. The gunsmith wasn't in today so I'll have to talk to him tomorrow. Hopefully he'll be able to help me out.

MileMarker81 · 02-02-2010, 11:29 AM

I went to the gunsmith yesterday. Here is my story.

I called the nearest Gander Mountain and talked to one of their gunsmiths. Yes, they did have a GO gauge for a 30 luger and they could look at it while I wait. It's a 40 mile drive for me, but they have what I need, so I head off.

I stripped the pistol to just the barrell/reciever and bolt slide before I got there to avoid having to check it in. I also removed the extractor and firing pin.

I handed it over the guy at the desk after telling him what I needed. About ten minutes went by and a really nice guy named Tim called me back to the window.

"We don't have any headspace gauges for this."

Grrr. I explained that I called beforehand and someone assured me that they did have the gauges, but it didn't matter. They didn't have them. That's life.

So, I told him my whole story and handed over the gauges that I had rented. I wanted them to have their own gauges for independent verification, but what can you do?

After about ten minutes, he called me back over.

He said that the gauges were the correct ones and that they was nothing in the breech or barrel preventing them from seating fully. That was kind of good news because it meant that I wasn't just being an idiot.

He said that it was very close and it may need "a couple of thousandths" reamed out.

Here are his three theories on why it failed the GO gauge:

1) It was always like this. Perhaps it came from the factory with a minimum of headspace.
2) Maybe the pistol is at the minimum of headspace and the gauge is at the max tolerance for minimum headspace. For a GO gauge the manufacturer would want to be a bit longer than a bit shorter. Gauges for rimless cartridges are hard to measure because it has to be from the "datum" line which is half-way down the neck.
3) Maybe it had headspace problems in the past and a _very_ skilled gunsmith milled down the collar but didn't ream it quite enough. There wasn't any obvious signs that this had happened, but a good gunsmith could do it.

He said that they didn't have any ammo to try with it but if it fully closed on a round and the bullet didn't show any signs of being forced in, he'd fire it. He'd be happy to order the reamers and do that work, but he didn't think that it was necessary.

I reached for my wallet and asked how much I owed him. "No charge. I couldn't fix your problem. Next time bring me something that I can fix." Did I mention that he was a great guy?

I should be getting some ammo today or tomorrow so I'll see how that goes.

Rob

policeluger · 02-02-2010, 11:42 AM

I have seen a lot of Russian reworks that need a bit of polishing with fine crocus cloth around hard wood dowel, but never a 20 commerical as they were very well finished, I was a bit hold off offering that advice because of this, but glad it all worked out.....being a bit tight/rough chamber it may have a few extracting issues until all worked out.....on second thought a fine frost of rust could have done the same thing....best to you

alanint · 02-02-2010, 01:38 PM

Just to be on the safe side, hold the gun well away from your face and body for the first couple of shots. Better still, find cover and fire the gun around a barrier with your body and face protected. Ideal would be a ramsom rest with a remote triggering system.

Not paranoid, just have seen too many things happen.

MileMarker81 · 02-03-2010, 04:29 PM

Quote:

Originally Posted by alanint

Just to be on the safe side, hold the gun well away from your face and body for the first couple of shots. Better still, find cover and fire the gun around a barrier with your body and face protected. Ideal would be a ramsom rest with a remote triggering system.

Not paranoid, just have seen too many things happen.

Sounds like great advice to me. Will do.

The ammo came today and it fits well. The bolt isn't forcing it into the chamber and it's closing all the way. I have to assume that the gauge is long.

I bought a couple of magazines with wood bases from cheaperthandirt when I got the ammo. Was that a bad move? Correct ones appear to be about $150 and I just don't have the pennies to spend on it right now.

Next up, the range.

Thanks for the help everyone.

Rob

01-30-2010, 11:33 AM	#1
MileMarker81 User Join Date: Jan 2010 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	An inherited 20's Commercial - too little headspace? Hello. I recently inheritied a 20's Commercial from my mother-in-law's estate. It was her father's gun so it has quite the sentimental value. All the numbers are matching but there is no clip. My boys (a 17yo and a 20yo Marine) want to shoot it at least once. The Marine will be taking his pre-deployment leave in about 6 six weeks, so I have until then to make sure that it's safe to fire. I've stripped, cleaned & inspected all parts and there is no obvious wear or cracks. The action is smooth. So far, so good. I rented a Go/No-go gauge set from an online gunsmith supply shop and the breech fails to fully close on the GO gauge. To double-check I made sure that everything was clean and checked the gauge demensions against the published SAAMI specs and it all checks out again. Hmmm. Do firearms lose headspace with age? It seems odd to me. Could this be a matter of old tolerances vs. new tolerances? All of the appropriate Nitro proofs are present so it had to be checked at least once in it's life. What do you guys think? Thanks in advance, Rob

01-30-2010, 01:26 PM	#5
Edward Tinker Super Moderator Eternal Lifer LugerForum Patron Join Date: Jun 2002 Location: North of Spokane, WA Posts: 15,935 Thanks: 2,034 Thanked 4,533 Times in 2,093 Posts	Rob, the standard line is "take it to a gunsmith and let them check it for safety". With Lugers (and I am no expert on things like this), the barrel and the extractor have to be lined up, so unless you have a mismatched barrel or mismatched or damaged breechblock, then its hard toget out of whack. I have never tried a no/no go gauge on any luger I have fired, although I'm more of a collector than a shooter anymore. Ed __________________ Edward Tinker ************ Co-Author of Police Lugers - Co-Author of Simson Lugers Author of Veteran Bring Backs Vol I, Vol II, Vol III and Vol IV

01-31-2010, 04:22 PM	#10
MileMarker81 User Join Date: Jan 2010 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks for the input everyone. I've called ten gunsmiths in a 30 mile radius of my house and no one has the tools on hand to check headspace for this pistol. I will keep trying until I find the right gunsmith. No worries, since I'm having problems Ill get it checked out. About the gages that I'm using, they are rented from Elk Ridge Reamer Rentals. This is a company that specializes in renting tools to gunsmiths so I have to assume that they are correct. (Imagine the liability of shipping bad gages.) They appear to be milled steel in roughly the shape of a round. The are hand engraved: "30 Luger GO PPG 3.00" and "30 Luger NO.GO PPG 3.00". I am using page 28 of this as a guide: http://www.saami.org/Publications/205.pdf These are hard to measure, but distance from the rear of the gage to the beginning of the necks are: (See photo) GO - 16.32mm NO GO - 16.59mm According to the SAAMI document, for a shell this distance is 15.893mm. Is that difference the required headspace? I don't have any ammo for this. If FedEx is to believed, that will change Tuesday. I have to say though, that I am not comfortable using live ammo to test anything. I have Zoom snap caps for this purpose for the other firearms but am unable to find them in this caliber. I'll see if I can talk a reloader into making me some dummy rounds. Attached Images

01-31-2010, 05:40 PM	#11
Ron Smith User Join Date: Feb 2004 Location: Orygun Posts: 4,243 Thanks: 118 Thanked 245 Times in 150 Posts	Something that you might check, is to see if there's a separated case stuck in the chamber. It's a long shot, but it does happen. Here's an example. Fired a .30 shooter with a handload that I have used in every .30 that I have owned. The previous round separated ejecting the lower half of the case. The subsequent round jammed itself into the upper half that was still in the chamber. When I finally got the toggle open this came out. Attached Thumbnails __________________ I Still Need DWM side plate #49... if anyone runs across a nice one. What ~Rudyard Kipling~ said...

01-30-2010, 12:44 PM	#2
policeluger RIP Join Date: Jun 2002 Location: Ca. Posts: 2,141 Thanks: 8 Thanked 89 Times in 54 Posts	They lose head space with firing, but not by aga alone....was the extractor keeping gage from closing......is this a 30 or 9mm.....and correct period mags are easy to come by.....I would supect the gage.....let us know and welcome here....

01-30-2010, 12:52 PM	#3
mrerick Super Moderator - Patron LugerForum Life Patron Join Date: Dec 2009 Location: Eastern North Carolina, USA Posts: 3,909 Thanks: 1,374 Thanked 3,110 Times in 1,510 Posts	Have you inspected the breech and barrel interior for corrosion? When testing headspace on rifles, you must remove the extractor and firing pin. It may be the same on pistols like the Luger. Does it look like the barrel was changed out at some point? (Does the barrel serial number match the frame?)

01-30-2010, 01:23 PM	#4
MileMarker81 User Join Date: Jan 2010 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	Hi Guys. It's a .30 cal luger. I removed the extrator and firing pin when checking with the gauge. The barrel numbers and frame numbers exactly match and so does the witness mark between the barrel and receiver. There are two digits under the sight that match the last two digits of the barrel/frame. I have to think that everything is original as it came from the factory. I can't see any obvious corrosion. There is certainly not anything foreign in it preventing the gauge from fully seating in the chamber. I could try to take some pictures, but the point-and-shoot camera that I have doesn't do well with macro shots. How do they lose headspace from firing? All of the forces are going the other way (pushing the barrel away from the receiver)and wear would make the headspace bigger not smaller. Maybe this is one of those counterintuitive things but I just don't get it. Anyone know of a good explaination? Every explaination of headspace that I've read so far has said that headspace increases with use. Thanks again, Rob

01-30-2010, 05:25 PM	#6
policeluger RIP Join Date: Jun 2002 Location: Ca. Posts: 2,141 Thanks: 8 Thanked 89 Times in 54 Posts	Firing does over time wear the chamber and bolt face, causing excess head space over time....when checking HS did you take the top off the luger so as to have little outside interferance, would you like to set up a time for a phone call.....I hate the key board.....maybe we can figer this out one to one......

01-30-2010, 09:19 PM	#7
LugerVern User Join Date: Apr 2005 Location: Virginia Posts: 563 Thanks: 1 Thanked 34 Times in 27 Posts	Georg Luger developed the 7.65mm cartridge from earlier 7.65 mm rounds. The 7.65mm Parabellum cartridge uses a shorter cartridge case than the 7.65x25mm Borchardt, 7.63x25mm Mauser, and 7.62x25mm Tokarev cartridges, which are the about same length. Make sure you are using the right gauge. Vern

01-31-2010, 08:52 AM	#8
alvin User Join Date: Jul 2007 Location: US Posts: 3,843 Thanks: 132 Thanked 729 Times in 438 Posts	If ammo can get in without obvious deformation, but "GO" gauge cannot, most likely it's the wrong set of gauges. If ammo cannot get in, then .... wrong gun. === [Edit] WARNING: This gun can accidentally discharge in disassembled mode. Play at your own risk and know where muzzle points all the time.

01-31-2010, 08:59 AM	#9
policeluger RIP Join Date: Jun 2002 Location: Ca. Posts: 2,141 Thanks: 8 Thanked 89 Times in 54 Posts	Alvin, Milemarker did state in first post that he "miked" the gages to be double sure.....??

01-31-2010, 07:15 PM	#12
policeluger RIP Join Date: Jun 2002 Location: Ca. Posts: 2,141 Thanks: 8 Thanked 89 Times in 54 Posts	Ron, he did say that all parts were inspected.....I can't wait for the end....

02-02-2010, 11:29 AM	#14
MileMarker81 User Join Date: Jan 2010 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	I went to the gunsmith yesterday. Here is my story. I called the nearest Gander Mountain and talked to one of their gunsmiths. Yes, they did have a GO gauge for a 30 luger and they could look at it while I wait. It's a 40 mile drive for me, but they have what I need, so I head off. I stripped the pistol to just the barrell/reciever and bolt slide before I got there to avoid having to check it in. I also removed the extractor and firing pin. I handed it over the guy at the desk after telling him what I needed. About ten minutes went by and a really nice guy named Tim called me back to the window. "We don't have any headspace gauges for this." Grrr. I explained that I called beforehand and someone assured me that they did have the gauges, but it didn't matter. They didn't have them. That's life. So, I told him my whole story and handed over the gauges that I had rented. I wanted them to have their own gauges for independent verification, but what can you do? After about ten minutes, he called me back over. He said that the gauges were the correct ones and that they was nothing in the breech or barrel preventing them from seating fully. That was kind of good news because it meant that I wasn't just being an idiot. He said that it was very close and it may need "a couple of thousandths" reamed out. Here are his three theories on why it failed the GO gauge: 1) It was always like this. Perhaps it came from the factory with a minimum of headspace. 2) Maybe the pistol is at the minimum of headspace and the gauge is at the max tolerance for minimum headspace. For a GO gauge the manufacturer would want to be a bit longer than a bit shorter. Gauges for rimless cartridges are hard to measure because it has to be from the "datum" line which is half-way down the neck. 3) Maybe it had headspace problems in the past and a _very_ skilled gunsmith milled down the collar but didn't ream it quite enough. There wasn't any obvious signs that this had happened, but a good gunsmith could do it. He said that they didn't have any ammo to try with it but if it fully closed on a round and the bullet didn't show any signs of being forced in, he'd fire it. He'd be happy to order the reamers and do that work, but he didn't think that it was necessary. I reached for my wallet and asked how much I owed him. "No charge. I couldn't fix your problem. Next time bring me something that I can fix." Did I mention that he was a great guy? I should be getting some ammo today or tomorrow so I'll see how that goes. Rob

02-02-2010, 11:42 AM	#15
policeluger RIP Join Date: Jun 2002 Location: Ca. Posts: 2,141 Thanks: 8 Thanked 89 Times in 54 Posts	I have seen a lot of Russian reworks that need a bit of polishing with fine crocus cloth around hard wood dowel, but never a 20 commerical as they were very well finished, I was a bit hold off offering that advice because of this, but glad it all worked out.....being a bit tight/rough chamber it may have a few extracting issues until all worked out.....on second thought a fine frost of rust could have done the same thing....best to you

02-02-2010, 01:38 PM	#16
alanint User Join Date: Mar 2008 Location: Marco Island, Florida Posts: 4,867 Thanks: 1,685 Thanked 1,916 Times in 1,192 Posts	Just to be on the safe side, hold the gun well away from your face and body for the first couple of shots. Better still, find cover and fire the gun around a barrier with your body and face protected. Ideal would be a ramsom rest with a remote triggering system. Not paranoid, just have seen too many things happen.