...and barely made a hole in the second.

This means that it only penetrated about 6 inches of water, or the equivalent of about 3 inches of flesh.

Not enough to be an effective Stopper.

How about the 12 Gauge with #8 birdshot?

Having a short barrel and no choke, it made a much bigger pattern, but also only penetrated one jug.

Not good enough for dependable Stopping.

Let's try Buckshot.

I was able to find some 20 Gauge Buckshot, some Winchester #3 Buck, with 20 pellets.

I was very surprised that it penetrated into the forth jug!

That's equivalent to over 12 inches of penetration into flesh.

More than enough, according to experts.

Who'd a thunk it?