To answer the question seriously, I'd take the shotgun in a New York minute.

When it comes time to really kill or be killed and carryability or concealment is not a factor, I want the most destructive weapon I can get my hands on. A Ma Deuce would not be unwelcome if it means dropping them before they have a chance to harm me.

Gunnery, gunnery, gunnery.
Hit the target, all else is twaddle!