Looks like the individual tubes experienced proof with shot and then possibly together later. I think after the 1891/1893 rules that they were having ox cart loads of tubes proofed before assembly. Now the new proof rules at the Zella-Mehlis facility were from September 1st 1911(these were rule changes whereas they 1891/1893 & 1939/1940 were law), so if the Eagle Crown over N Nitro is present it was proofed in prep for the new rules.
I'll just about bet that Axel or Shotgun Charlie has one of these coil spring scatterguns. Sauer had an offering early on before the A&D action came to the forefront.
Kind Regards,
Raimey
rse
