Originally Posted by johnbrowning
The fact that those particular rounds keyhole, is that good or bad?
On soft tissue, its not a bad thing.
Key-holing reduces accuracy but can substantially increase stopping power by creating a much larger wound cavity. This was demonstrated by the early M-16s in Vietnam. The twist rate of 1:12 was too slow to give ballistic stability, so those early rifles had marginal mid-range accuracy but where incredibly effective at closer range. When the design was changed to a faster twist the M-16 became a much more accurate rifle but there was a noticeable decrease in one-shot stopping power.
That said, not all wadcutters keyhole in all handguns. It depends on the caliber, bullet weight, load or velocity, barrel length and rifling twist rate. It's easy enough to test at the range, though. This will tell you if the round keyholes in flight, but not the performance at impact.
But given the assortment of high performance, essentially guaranteed high-expansion SD ammo on the market I'd go that direction rather than leave the performance to the vagarities of a round that may - or may not - keyhole at the critical moment (and with the attacker's particular clothing).