Sorry, work has been kicking my ass ever since I got back so I didn't check in lately (you know how you pay a big price just to arrange the time off and the logistics and then there's everything that piles up that is waiting when you get back). Sorry to confuse but I did mean standard 2 3/4 shells in my original post. Still, the hot loads are a challenging load to produce but fun to shoot.
There's a reloading recipe with Hodgson Long Shot powder (compact, but packs a punch), good quality Winchester AA hulls and compressed wads that can get you to 1.5oz with just a moderate amount of bulge in the crimp. The breech and muzzle pressure stays reasonable for any gun made in the past 30years but still comes out at about 1350 fps. Patterned really well in my Rem 12ga 1187 SuperMag and fits 5 shells of this size in a standard mag.
I am hunting with a young flushing dog in ditches and public spots with smart, wild birds. They were getting up at 30-40 yards to start for an average shot and in windy conditions they were moving fast in the air. You don't need loads this hot to take birds but in these conditions, but I get much cleaner kills in this situation when I can reach out and swat them down. As long as I can get reliably get birds at this distance, I will take the long shots. Rather than continue to lose birds, I will change shot size because the laws of physics says they will hit harder under similar conditions.
With little wind and dumber birds on opening Saturday, I took 5 birds with 7 shells. I shot an U/O for my first 20 years in SD so I learned to make good first and second shots. With my dad slowing down I now have to get on a second or third bird in a flush, thus the upgrade to an auto.
It's not unusual in SD to pickup a variety of roosters. I've regularly handled just-colored birds, pen raised, this years full grown and a 2 or 3 year old birds and got them 50-75 miles a part in a season. There is a difference between how easily they drop and what their feather thickness you can feel when you handle them. Could be local flock genetics, feed available and I think weather conditions in my experience.