I have hunted with shotguns and buckshot for many,many years.I have always shot 3" winchester #4 buckshot.winchester is the brand that my gun likes.I have use #4 buck for deer,hogs,and turkey for most of my hunting life and have found they work well and have a few more pellets per shell;thus makes for a better pattern.
You may give them a try and see how you like them.they will take down a deer or hog just as well and any other size.my photo book will testify to the results.