Your 7 1/2 is fine for small birds like pigeons and doves, yeah I eat both,. but like the others said if there was a one shot sized for almost everything it would have to be #6. Squirrel to turkey it will do the job. I have some buck but I found anything that needs more than #4 shot might as well take a slug.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.