Sundance,
We're talking about a little 9mm bullet here, so the analogy holds true.
The 9mm has no stopping power. That's been proven time and time again, and I believe that even the 9mm advocates will agree. So we're talking 9mm choices in either two ways:
Quantity versus quality, where more bullet capacity will stop'm, or
Quality versus quantity, where shot placement is key.
In the latter case, bulk-packed Remington 22lr will do the same job. So I assume we have to talk about the former - quantity. In quantity, it won't matter if you have silver filled hollow points cased in lead, because the expanded 9mm/380 family doesn't have enough metal in it to fill a teaspoon (Ever seen an expanded .45? Looks like a silver dollar. Expanded 9mm, if under the most ideal circumstances, might expand to the size of a quarter.). You're trying to fill your target with lead to effectively stop it.
Relying on shot placement would be a nice luxury, but you can't always count on being able to do it. That's why body mass is preached for high-stress situations.
Thus the 30d nail analogy. I once had a 30d nail go through my thigh. Didn't stop me at all.
Of course, there are exceptions to every rule.