Generally I've had 2.75" 00 buck loaded for my shotguns last 30+ yrs. At times do to certain circumstances been special loads or #4 Buck. I would use 3 1/2" or birdshot if it was the only thing I had at the time. While we may plan for the fight to be close range indoors it may go to outside or threat maybe 4 legged outside. I want to ensure I have penetration and reach the vitals (I live in a rural area)
CD