Back when a common 20g load had less payload and the 7/8 oz load came around, I'm sure there were many that said it was too much to be efficient. My experience tells me a 1 oz load in a 20g is an effective killer even if it's not a technically perfect load in some people's opinion.

Some will tell you 1 oz in a 20g causes too much recoil, then, in other threads, tout how their 16g guns are built on 20g frames and just as light.