I went over to the range this afternoon and put the left barrel of my DHE 12ga straight grip 30" Titanic bbls on paper to see how it was actually performing with a 7/8 ounce load of magnum 8's. Barrel has a choke constriction of .038.
The load was AA hull, Fiochhi 616 (209 type) primer, 16.5 grains of Red Dot, Claybuster brand copy of Win AA12SL wad, 7/8 ounce of Lawrence brand magnum 8 shot. (My MEC 7/8 bar throws slightly heavy, 29/32 of ounce when weighed, 385 #8 pellets)
The pattern at 40 yards was 318 out of 385 pellets in a 30" circle for 82.57% I deliberately held low for this shot because the gun is stocked for trap shooting and it shoots a high point of aim.
Not much is going to get away from this 7/8 load out to 40 yards. If you have not tried shooting clays with a 7/8 ounce load in a 12ga you should give it a try as they really perform well, give much less recoil and stretch a bag of shot a little further.