Gomann Berlin

[klaus 3338]

Friedrich Gomann got a patent on the 4. April 1926 for his conversion unit in calibre 4mm M20.
The muzzle protector was refined and used by the Police.
Of interest is the date of the patent because of the acceptance mark which we also can find on the receivers of several Lugers of this time.
Attached are the patent drawings and some photos.

[Kansasman]

Hello all,

I purchased this a few years ago and thought it was some type of Luger training accessory or an extra part with a 22 kit? Anyone have any ideas? It is marked Erma with the Waffen Eagle R stamp on it.

Thanks in advance

[Edward Tinker]

From what I have always been told, these have two purposes

1. put on the muzzle and then it can be used to clean from the front and not damage anything on the crown

2. they are used to attach the 22 training for a single shot - I have one of these

[Kansasman]

Ok that makes sense, I wonder why there is limited information about them on the net? What should one sell for? Thanks again

[Edward Tinker]

I have bought them for $50 - $150 - depends on how they are marked

[klaus 3338]

Originally Posted by Kansasman

Hello all,

I purchased this a few years ago and thought it was some type of Luger training accessory or an extra part with a 22 kit? Anyone have any ideas? It is marked Erma with the Waffen Eagle R stamp on it.

Thanks in advance

It´s a Police accessorry and was used with an 4 mm M 20 barrel by the Police. A .22 cal. version is commercial.
By the way: the eagle R is a Police acceptance E/B

[klaus 3338]

Originally Posted by Kansasman

Hello all,

I purchased this a few years ago and thought it was some type of Luger training accessory or an extra part with a 22 kit? Anyone have any ideas? It is marked Erma with the Waffen Eagle R stamp on it.

Thanks in advance

Originally Posted by Edward Tinker

From what I have always been told, these have two purposes

1. put on the muzzle and then it can be used to clean from the front and not damage anything on the crown

2. they are used to attach the 22 training for a single shot - I have one of these

Edward,
can we see some pictures of the .22 cal. barrel, please.
I could never get one.
Thanks
Klaus

[klaus 3338]

I was not sure but I found one of my older threads about the different types of conversion units.
http://forum.lugerforum.com/showthre...onversion+unit

[Schupo]

Here is an example of the police marked ERMA conversion unit. These single shot training units fit the 9mm P.08 by the way.

[sheepherder]

Originally Posted by Schupo

Here is an example of the police marked ERMA conversion unit. These single shot training units fit the 9mm P.08 by the way.

Very interesting! These sub-caliber conversions lock on the front sight base rather than a chamber lock like the .22 Erma conversions (stepped & flanged barrel insert).

George, is the 4mm cartridge center fire??? I suppose it would have to be...

[Kansasman]

Very interesting! Thanks guys

[kurusu]

Originally Posted by sheepherder

Very interesting! These sub-caliber conversions lock on the front sight base rather than a chamber lock like the .22 Erma conversions (stepped & flanged barrel insert).

George, is the 4mm cartridge center fire??? I suppose it would have to be...

There is/was a 4mm M20 cartridge. And it's centerfire. It has no powder i'ts propelled by primer alone.

[Schupo]

Originally Posted by sheepherder

Very interesting! These sub-caliber conversions lock on the front sight base rather than a chamber lock like the .22 Erma conversions (stepped & flanged barrel insert).

George, is the 4mm cartridge center fire??? I suppose it would have to be...

Yes, the single cartridge is loaded by hand and extracted with a rod run through from the muzzle. Here is a period description.

George

[Edward Tinker]

I have also seen them marked eagle 359 (??) and so I was not of a firm belief if they are always police. I sold that one, the one I kept says S.B. 1703

It has a spring action that you push and then it holds fast to the barrel

Also, somewhere I have a couple of 4mm - my friend Russ had a box of them once. But heavens knows where it is...

[Schupo]

Ed,

The military used these Einstecklaufe as well so your WaA marked one was not police issue. Your Schutzpolizei Berlin marked example and mine most certainly are. These are complicated little things and a lot of trouble to use.

George

[sheepherder]

Originally Posted by Schupo

These are complicated little things and a lot of trouble to use.

George, I find that a curious comment...I have fired three different .22 Luger sub-caliber conversions in the past Summer and didn't find them much trouble to use...

Ed's 4-piece 4mm conversion doesn't seem all that complicated either...(Although I would prefer the 4mm muzzle clamp that uses the interrupted rear nut)...

Could you explain further???

[kurusu]

Originally Posted by sheepherder

George, I find that a curious comment...I have fired three different .22 Luger sub-caliber conversions in the past Summer and didn't find them much trouble to use...

Ed's 4-piece 4mm conversion doesn't seem all that complicated either...(Although I would prefer the 4mm muzzle clamp that uses the interrupted rear nut)...

Could you explain further???

Maybe because the 4mm M20 (the one on the left) as no rim and might get stuck after fire.

[sheepherder]

Originally Posted by kurusu

Maybe because the 4mm M20 (the one on the left) as no rim and might get stuck after fire.

Attachment 44070

Mario, is the 4mm barrel insert rifled or smoothbore??? Primer-only ignition can't be all that powerful, even for a .157" projectile...

A barrel insert installed from the muzzle leaves the chamber end unsupported...The Luger chamber is ~.386" dia and the bore is ~.346" dia...So the barrel insert is unsupported at the chamber end by ~.040" total...(.020" radially)...So you can't have too much chamber pressure or it would expand the insert, making it 'difficult' to remove...

[kurusu]

Originally Posted by sheepherder

Mario, is the 4mm barrel insert rifled or smoothbore??? Primer-only ignition can't be all that powerful, even for a .157" projectile...

A barrel insert installed from the muzzle leaves the chamber end unsupported...The Luger chamber is ~.386" dia and the bore is ~.346" dia...So the barrel insert is unsupported at the chamber end by ~.040" total...(.020" radially)...So you can't have too much chamber pressure or it would expand the insert, making it 'difficult' to remove...

Now you got me. This contraption was popular in Germay where it didn't need registration ( there were pistols exclusively for this type of cartridge either made on purpose or modified ). Here I've never seen one so can't really answer.

Apparently nowadays these things must be registered as firearms in Germany. So my guess is they will be headed the same way as the dinosaurs

[klaus 3338]

Originally Posted by Edward Tinker

I have also seen them marked eagle 359 (??) and so I was not of a firm belief if they are always police. I sold that one, the one I kept says S.B. 1703

It has a spring action that you push and then it holds fast to the barrel

Also, somewhere I have a couple of 4mm - my friend Russ had a box of them once. But heavens knows where it is...

Edward, it`s a Gomann conversion unit...
http://forum.lugerforum.com/showthre...onversion+unit