1-1/4 ounce won't necessarily make a bigger pattern but it will make a denser one than 7/8 ounce, with more pellet strikes per bird
at any given yardage. And pellet strikes and penetration are the name of the game. Now, compare those modern vintager-type low pressure loads for duck hunting with the common "High Brass" 12-gauge 1-1/4 ounce lead shot loads that I used when I was a kid, and still use today for heavier game when lead is allowed. They came in at about 1330 fps. And that period 12-gauge low brass field load with 1-1/8 ounce had about 1225 speed. Most duck hunters back then would load up with those high brass shells to cover any/all yardages, a no brainer. And old time small game hunters often had low and high brass shells in right and left barrels respectively. Nowadays I will think about those shot load and velocity parameters when choosing the gun and shells for whatever I'm hunting. And if I don't have a SxS that will handle such loads I'll relegate it to clays and choose another gun for hunting that will.
I know this will get some readers irritated but I just about get shivers whenever someone talks about how light shot charges will pattern way better and are just as good or even more effective than heavy ones, also about so-called square loads having some magic quality that makes them much superior to others in the same gauge but with a longer shot column. One last comment when comparing something like a 7/8 ounce load in 12-gauge to a 1-1/4 ounce one .... when the gun goes bang that extra 3/8 ounce has to go somewhere. Ha!
