Dayum! We give up. Our argument is refuted.
I don't agree. I think the ballistics show exactly why you shouldn't use birdshot as a defense round.
I keep 00 loaded at home. I think it's a very versatile load to buy in bulk. I've found that 2-3/4" @ 1300 fps min works best for a wide range of models, regardless of high/low brass. I think versatility of models is important in a stockpiled ammo.