IMO more than enough. I have shot several with a 20 ga and have had not trouble. I wouldn' t shoot it over 40 though, even if the pattern is good on paper. That is reaching for a 20. You may take a little flak for shooting a smaller gauge gun, I take quite a little from my friends. Tell the naysayers to go stand at 40 yards and you will shoot them in the head, bet you won' t get many takers.