Shot barrels on a German 16-16-9.3x72r I have show;
2Gr Sch P/28.3Gr Bl.
This gun was proofed in Feb of 1907. This is of course essentially 1 oz of lead. 2Gr for the powder = 30.86 grains.
I am of the opinion, though could be wrong, that in 1907 Schultz was still considered a 42 grain powder, IE a 3 dram equivalent = 42 grains. If this be the case then this 2gr load of Schiltz is only about a 2.2 DE charge. This seems a very light powder charge for an oz of shot in a 16 gauge. On the other hand I have heard that German proof laws prior to 1912 stipulated proof charges based on Black Powder, even when Smokeless was used. Therefore most did not smokeless proof shot barrels during this era & those who did specified a very light powder charge as the service load. This gun would seem to bear this out.
If however this was proofed with a 32 grain schultz then it would be a near 3DE charge. Am not sure when the 32 grain Schultz was introduced.
