Gomann Berlin

[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