Here is some other reading of interest

http://castboolits.gunloads.com/showthread.php?75108-9-3x72R/page2

16 in circle shotgun caliber 16/65
16/1 full choke
Letters are manufacturing markings to allocate every step to a certain armorer
118/35 stands for the caliber of the rifle barrel 9.3x72R (according to the Reichsgesetz)

The weapon was proof shot with smokeless and ‘Schulzepulver’ new type, proof house Suhl
1905 was the change to smokeless

The sequence of powder is:
1880 M71 military powder
Around 1895 ‘Schulzepulver’ civil market
1905 smokeless
Therefore 2,5 g Sch.P. stands for 2.5 gram Schulzepulver with 29.3 gram lead bullet
2,1 gr B.L. stands for 2.1 gram flaked powder Stmg stands for steel jacketed bullet…”

USAF RET 1971-95 [Linked Image from jpgbox.com]