[alricb]

Normal shotgun rounds are filled with a number of pellets; the smaller the pellet, the more you can fit. Birdshot: small pellets in large number, Buckshot: large-ish pellets in small number. A slug is a massive (18.5 mm diameter for 12 gauge) single projectile used in a shotgun shell.

[lifeisstillgood]

I got that - I just did not understand the implied "birdshot and slug at the same time"