C&B is just as lethal as it was during the Civil War and was still used afterwards for many decades later. If it was the only option then yes my 1847 Walker is just fine and my 1851 Navy is great for close up work. But I am an old Sergeant who knows how to keep his ammo stocked and ready so it's unlikely I'll never run out, even in the fiercest assaults' on my compound. Like most here I stock thousands of rounds for each caliber I have. A little off-topic in a way, but my mind set was formed long ago sitting on the tarmac watching the Helicopters come back to pick my team up and one crashed on the base and a couple others were barely able to land while on fire and shot up. That's when I knew my 200round combat load wasn't enough.
But back on topic, I've never been without ammo and even C&B will do a job for a brief time dealing with a crook. It's still the only option for some folks today.