I have the 1906 Belgian proof loads. For 16ga the 3rd proof load was 9.8 grams of powder with 37.7 grams of shot. This was for a service loading of 4.9 grams of powder with 28.3 grams of shot. "The third test if on the barrels with the action attached. The barrels to be struck up and smoothed, and the insides clean. The action to be finished, or in the finished-file state."


Hope this helps,

Pete