From the interview with the private armed citizen, a semi auto with slugs could of done some good work.
I'm all ears when you talk about bears, but sometimes you veer into strange territory. Your original question was about body armor and two calibers, and then you throw out that some guy shot engine blocks with .22-250. Wonderful. I shot a .50 Maxi-Ball through a junk car but I wouldn't recommend a muzzleloader in a gunfight.
Failrure2stop nailed the answer. In the interview posted under 'mindset' the guy in Texas told everyone what he did, which is what anyone else in that situation should do: shoot where the armor isn't.
"Gunfighting is a thinking man's game. So we might want to bring thinking back into it."-MDFA
Beware of my temper, and the dog that I've found...
This was a theoretical caliber penetration question, and I was frankly surprised to hear from my friend, Jim Brockman, about the .22-250. I certainly wasn’t making a platform or caliber recommendation for someone else.
That said, based on my experience with my .300 WM, if I had the opportunity to fire one surprise shot from 50-450 yards at that shooter to end that fight, I have done some of the best shooting in my life with that bolt gun and a Barnes 180 at just under 3,000 FPS.
Likes pretty much everything in every caliber.
Doesn't penetration advantage usually go bullets with high sectional density? Don't the 6.5mm bullets typically have a sectional density advantage?
I have seen a .300 WM go right through steel rifle plates when nothing else would, with conventional bullets. I dont know about ceramic, it seems to do a little better then steel.
We could isolate Russia totally from the world and maybe they could apply for membership after 2000 years.