Can anyone tell me more about this flash hider and takedown tool?
 

Came by these separately. The tool is a repro, isn't it?

As for the --so called-- "flash hider", I *don't* know what it is. Rarity? Value? Military or police issue? Production date? What does the s/n mean? When were these typically used?

http://i1280.photobucket.com/albums/...ps533c3b98.jpg

Not a flash hider, it is either a 22/4mm adaptor for a Luger or it's also a cleaning guide. Worth $50 to $125 depending on age and how it's marked.

Interesting. I could have sworn I saw this exact device touted by Simpson's as a "flash hider". The one pictured on their website I recall was marked to match a police luger, if I recall correctly???

The tool was made in East Germany in the 1950th by the Ernst Tählmann Werke (Ernst Tählmann factory).
The muzzle protector was also used with the conversion unit by the police in caliber 4mm central fire. The number on it may be the number of the Luger (either the Luger serial number or the Police number on the frame) with which the conversion unit was used. My English is not good enough to say all but some members will do.

Use it as a Flash hider for a 9mm and you will have a VERY unpleasant experience since the hole through it is MUCH smaller than 9mm. Let's be careful out there...

Only partially correct John. The OD of the 4mm adaptor that goes with this muzzle device is 9mm, so the hole is large enough. But without the insert adaptor the alignment is not precise so you are correct that firing a 9mm round through it would most likely be a very unpleasant experience.

At any rate, calling this device a flash hider is ridiculous but Simpson's isn't the only party guilty of this misnomer.

Found that in the "Ministerial- Blatt für die Preußische innere Verwaltung" with date of 23. Mai 1928: ....the hole of the muzzle protractor is to be enlarging to 9,07mm. Reason was that the muzzle protector as a part for cleaning the barrel molded the cleaning material on the cleaning rod. That was not helpful to clean the barrel.
Interesting is that only the muzzle protectors (as can be seen on the added pic) were enlarged. The Erma was not. That would mean that the Erma "muzzle protectors" were never used as it but were only used with the 4mm barrels.
The rifling of the Gomann barrels is different to the Erma barrels.