Heinz,
A very cogent commentary, and some useful conclusions which advance the topic. The Ludwig Loewe reminder is very interesting. For the record, I've brought the illustration and description downscreen for the comparison.
Example 01--Vickers. Suspicious.
Example 02--KOL. Definite rebarrel.
Example 03--1900 American Eagle. Perfect witness mark, single strike, single instrument, shows no misalignment even under high magnification. Reblue.
Example 04--S/42 1936. Not perfectly aligned, all other evidence points to the barrel being original.
Example 05--Erfurt LP-08. Perfect witness mark, single strike, single instrument. Apparent mislignment is artifact of lighting and steel surface, under high magnification the bottom of the strike is aligned.
Example 06--Modern rebarrel. Presented for contrast.
Example 07--1917 Navy. Two strikes, misaligned by less than 1/4 line width. All other evidence points to the barrel being original.
Example 08--1929 Police. No barrel mark.
Example 09--byf 42. Nickel-plated, barrel apparently removed and reinstalled.
Example 10--1917 LP-08. Two strikes, aligned, all evidence is barrel is original.
Example 11--1918 LP-08. Rebarrel--barrel is period/authentic LP-08 barrel, but is not matched to receiver.
GT,
Another useful practical perspective, thanks.
I ran into another comment by Gibson, p.94 (if I can be forgiven momentarily for the secondary source). He notes that headspace problems which might have been noted during inspection of the barrel/receiver/breechblock assembly could not be rectified by facing the receiver or barrel flange (in the case of excessive headspace); or by adding a spacer (in the case of too little headspace); because of inherent design features of the Luger. Presumably he means here that these changes would offset the front sight and the extractor groove.
--Dwight