Why don't shotgun slugs and shot use full metal jackets and why

Byrna Less Lethal Shotgun Ammo: Field Tested - Firearms News

How are total metal jackets used differently from full metal jackets? - Quora

Why do shotgun shells have brass or steel encasing the base while the rest of the shell is composed of paper or plastic? Is it necessary? - Quora

What's a Full Metal Jacket?

Full Metal Jacket Bullet - Interesting Things To Know

Why do shotgun slugs have a wad instead of being just a bullet with a casing and slightly larger slug? - Quora

How to Get the Best Accuracy with Shotgun Slugs

Ammo 101, Tactical Experts

FMJ vs. JHP - What Bullet & Ammo Is Best For You?