For many, many years Luger experts have believed that the Circle-B proof mark on the left-side receiver of the M1906 Brazilian Contract Lugers were to indicate a contract for Brazil besides the extractor marking being in Portuguese which is logical.
On a recent post about a fine and quite rare M1906 American Eagle Luger pistol (in caliber 9 mm Parabellum) having the same stamp under the barrel serial number, my dear stubborn friend Ron Wood (who still wants to believe the drunk 'Russian' Luger theory
) made the following comment to the proud American owner:
"The circled B marking was used as a receiver proof on the 1906 Brazilian contract Luger, and for some reason a DWM barrel inspector subsequently chose to use it as his acceptance mark (it is not a left-over barrel from the Brazilian contract as that would be a 4.75-inch barrel in .30 caliber)."
His comment made me think deeper for the correct reason which has even puzzled Luger experts for ages. Me being a Genius 😇 (which is my middle name initial), I now believe that I have discovered the actual reason for the use this stamp according to its placement on a Luger pistol, not to mean for a Brazilian contract Luger in caliber 7,65 mm Parabellum with a 4 3/4" slim barrel.
With reference to information that I had also researched regarding the M1908 Bulgarian Contract Luger (with a DWM logo being above the chamber and several of these pistols having a C-suffix serial number), I discovered that this arrangement was making reference to the DWM 9 mm Parabellum cartridge with the code DWM 480 C to help enlisted soldiers not to get confused with an earlier issued pistol in caliber 7,65 mm Parabellum at the time (around 1910-12) when several foreign nations were wanting to procure the more powerful 9 mm cartridge for their military.
After making some research and observations, I decided to apply the same logic to the Circle-B proof mark on the Brazilian Luger - and I discovered that the 7,65 mm Parabellum cartridge DWM 471 B happens to indicate 7,65 mm Swiss Parabellum (two piece case), which has the same design specifications as the Brazilian Luger pistol with a slim barrel.
I wish that this important information between pistols and cartridges will widen the knowledge and history by different collectors - being aware that the German DWM factory did everything for a reason - including with the safety markings on a 'Russian Luger', which is actually another Bulgarian contract Luger using the 480B cartridge - where the B stands for 'Bulgarian'. 🤪
Have fun,
Albert