Why don't you just stick with the load it was designed and proofed for? Why do you need the extra 1/8 ounce? It seems to me that it is just not that important. If you want to shoot 1-1/8 oz loads then get a 12 bore. At any rate, the best load for a 16 bore is 1 ounce. It will pattern better and be a little easier on the gun. I have found a 1 oz load in a 16 gauge double to be one of the most lethal loads around. It has a very short shot string and hits hard.