Data on Luger barrel thread specifications

[Norme]

Hi Don,
My statement is based on observation, the "witness marks" on military Lugers that have seen a lot of use frequently indicate some over tightening. Also since the only other such marking on military Lugers is on the front sight it seems like the most logical explanation. If you can come up with a more rational explanation i'd like to hear it.
Regards, Norm

[G.T.]

Having re-barreled & barreled a considerable number of P.08's I have a totally un proven theory on what the witness marks do, and what they mean?
One thing I found interesting, is that no mater where the barrel witness mark is or ends up, the mark on the receiver is always dead center on the receiver bottom? Ok, no big surprise except it means that the initial receiver mark and the barrel marking may have been applied at different times.. Ok again, why? Why not just screw the barrel on and nail it with a mark and say finished? Well, I think that is what they wanted to do, but the real world accuracy boogieman just wouldn't let them off that easy...
My theory is the receiver comes with the witness mark, the barrel is screwed in and it is mechanically set to zero, then it is witness marked making a new mark on the barrel in concert with the existing mark on the receiver. The barreled receiver goes on it's merry way thru production right up to the very end, where it was dynamically fired to establish real zero and the barrel was slightly adjusted, or not, to obtain what they considered acceptable accuracy... As a result, it may have been right on, explaining weapons that show perfect alignment, or slightly off for weapons that required adjustment? What else could it be that they would disturb accurate existing alignment marks? Just my theory.. best to all, til...lat'r....GT
BTW, Normes theory is relevant as well, makes sense, although I've not had any barrels migrate on me yet, but, still wondering, what other reasons could there be?
BTW Squared! It also seems that they did the final barrel correction outlined above, I suspect, in order to keep the front sight centered and indexed. So when it arrives in the field, it can be drifted both ways equally, for each unique shooters needs if necessary? Almost all nice P.08s I have seen, are dead center on the front sight base and blade??

[DonVoigt]

Originally Posted by Norme

Hi Don,
My statement is based on observation, the "witness marks" on military Lugers that have seen a lot of use frequently indicate some over tightening. Also since the only other such marking on military Lugers is on the front sight it seems like the most logical explanation. If you can come up with a more rational explanation i'd like to hear it.
Regards, Norm

There has been much discussion on witness markings and no conclusion that I recall.

They make some sense if one wanted to remove and re-install a barrel.

Many witness markings do not align, neither were they struck at the same time with the same instrument on the flange and receiver.

Some years back Dwight Gruber was doing a detailed study of the witness marks and what they might indicate, and when they were applied.

I believe that in this case logic has little to do with the presence or absence of the witness mark.

With some 40-50 ft lbs of torque applied to seat the barrel,
I do not subscribe to the rotational torque from firing being able to "tighten" the barrel though.

And what about the witness marks that don't align the other way?

A puzzle for sure!

Maybe Dwight will chime in with his idea or conclusion.