I used a 410 with 2 3/4" shell #6 shot, it never failed me,
I think 12GA is a little overkill
Ya know, it don't matter to me what folks use on rabbits. But you brought up some real good, very old memories for me.
I was taught growing up on the ranch to use a 'single shot' on my rifle/shotgun. So at 10 years old, I was given a Savage over under .22cal on top and .410 on bottom. Dad said, "son, learn to make the first shot count..." Single shot
larger bore rifle for deer. 30-30.
For the next several years I took more dove, quail, rabbits, tree rats "and even turkeys" (being taught to call them in 'real close') with that Savage, than you could skake a stick at. Out of all the guns in my safe, and all the years of guiding hunts, and my own 'personal hunting' with "various hog legs , shot guns and rifles", I can honestly say, the Savage .22/410 has killed more game than any gun in my safe. Countless numbers of rabbits, and other game, and tons of varmints, from coyote's to big Oklahoma Jack rabbits every eveining on the winter wheat fields. On and on.
I got NO real big point here. Just brought up memories of a 10 year old, back 50 years ago in the woods, learning to make the first shot count
I really don't remember which took down the most rabbits, the .22cal or the 410, but I can surely tell ya either one is plenty enough. Then they gave me a Hawes .22 cal six shooter and cowboy scabbard, and that became the Squirrel and bunny shooter. I am thankful to my late dad for teaching me this way, and have passed it down to my kids as well. I have never seen my son use more than one shot on small to large game at now 28 years old.
Still got that Savage, and hope to teach my three grand kids the same way
Thanks for the reminder. It was nice (for me) to take a few moments today and "think back," on all those good memories..
OP...Ya got more than enough gun for what your wanting to hunt, If your pattern is that tight 'as you say', get in close as heck and take only head shots man. A little .22 or 410 I would prefer, 'but to answer your question', with the 20ga, get in close and take 'head shots' so you'll have good clean meat..
Stay Safe Hoss, and good shooting/hunting. Have fun !