So you wouldn't want 12 or 20ga slugs to deal with something dangerous like.....bear? Those are low SD (like 0.12), low expanding projectiles. I'm guessing no one in bear country ever carries a Rem 870 pump for that scenario....
The SD on an unfired Brenneke slug is 0.130, if it expands to 80-cal and loses 10% of its weight it goes down to 0.100. Meanwhile, the SD on a 180-grain bullet retaining 70% of its weight and expanding to .50-cal is only 0.07. Hmm.
