I remember in the 80's there was a lot of work put into international trap loads by Ballistic Research. I loaded a lot of their loads with, I believe, their International Target Driver wads. I shot for a couple of years with 7/8 oz loads at around 1400 fps. My guns all patterned them extremel well. Recoil was very mild even compared to a regular AA target load, much less the handicap loads. A lot of people poo-pooed them until they shot them. The most dramatic effect was the way they shot at increased distances. I have seen the smae thing in 28 ga guns. Until they were unavailable my go to shell was Polywad Gram Crackr. It was a 5/8 oz load of nickel plated 5's loaded with a buffer at a pretty healthy velocity. Recoil was mild and there appeared to be no shot deformation at all. I use a 30" 28 gauge double with cylinder and skeet for quail and doves. With these loads I can make consistent clean hits and kills at 40 - 45 yds. With quail I use a spreader in the first barrel on a covey rise and a Gram Crakr in the second barrel to allow the birds to settle on a flight path before the second shot. Doubles are pretty to accomplish with this combo.
I think the general rule I have is to use as light a lead charge as possible that achieves an effective pattern at the target distance and then drive them to a maximum velocity that doesn't disrupt the pattern. Those two rules may not seem compatible, but if you start with the minimum charge that patterns effectively at the target distance, the combination of this and the acceptable max velocity you will end up with a comfortable load to shoot that operates at low pressure level but kills with authority. The caveat is that the load development depends on powder, wad, shot(size, charge, type) and choke. This requires quite a lot of development. However, when you find one that does all you want it is pretty magical thing to shoot.
