Not real sure about your question. I do know of store bought loads of 1oz slugs that run 1600fps. Doves are easy to kill, but hard to hit! Just use the Dove/Quail loads form your local gun store. If I can't find the load in my reloading manuals, then I don't mess with it!
Yes. hes simply using a 1 oz slug load and instead of a slug hes loading with a wad and shot.
I don't get the uber fast 'dove' loads. Doves are freakin easy to kill. You can actually thump them in the head hard enough to kill them,. You don't need anything faster than 1200 fps. in fact my favored load for doves and sporting clays is 1 1/8 oz at 1145 fps.