I am curious why some writers pick a less powerful weapon in their stories (e.g. a 20 ga shotgun) when your life is dependent on the killing power of your weapon?
For example: A standard 20 ga shell holds about 9, #1 pellets (0.030" dia) while a standard 10 ga shell holds about 18, #00 pellets (0.033" dia). The 10 ga load has twice the pellets and the pellets are heavier. The heavier pellets travel further, and at the same range they deliver a higher impact energy.
Yes a 10 gauge (or the more common 12 ga) has a higher recoil than the 20 ga, but if you avoid the magnum loads, the recoil is not that bad.