sounds like you have one of the finest shotguns ever made...
fact is, the pre ww1 sauers are my favorite guns...
your gun was made to shoot smokeless loads, so limiting it to black powder loads is not necessary...
one ounce field loads, moving at 1200 fps or less from the muzzle, should be just fine for this old gun...
but, as with any old gun, have it checked over by a knowledgeable gunsmith before shooting...
if you ever decide to part with it let me know via pm...
meantime, enjoy...
https://ammonerds.com/product/16-gauge-fiocchi-game-1-oz-8-shot-lead-11165fps-25-rounds-16gt8/
