More shot in the shell does not mean more shot in the pattern...

I shoot a 3 inch Browning B-80...With a .640 Hastings...

With 2 ounce loads I have holes...I moved down to a 1 7/8 Remington Nitro and the holes dissappeared and get good dense patterns...

I would drop down to a 3 inch shell...Start with 2 ounce loads but don't be afraid to go to 1 7/8 ounce loads as well...

The 3.5 shell was developed for steel shot and waterfoul hunting, they are not always the best for heavy turkey loads...The theory is that because of the longer shot column the shot in front actually holds back the shot in the back, which actually pushes into the shot on top and blows a hole in the pattern...

I'm not saying that you can't find a 3.5 inch shell that will pattern, but I do know several guys that have 3.5 inch guns that have gone to 3 inch shells for turkeys...