Help me with this MP43/1 part

[dect]

What is this? I've asked many people and nobody knows what was this used for.
It was described as a "Metalllehre zur MP43", dimensions unknown.

Any ideas?

[rdp91356]

MP43 Metalllehre

Well Babelfish translates it to "metal teaching" so I'm guessing it's some sort of guide used in assembly or manufacturing. It's not part of the gun itself.

[P08]

Lehre is something similar to what you americans refer to as "gauge". A measuring object of some sort.

[dect]

Mystery is probably solved (thanks to Claus Espeholt) - John Cross, one of the StG experts claims that it's a firing pin shape and protrusion gauge