[ROFL1] I dunno if they even make +P .25ACP. I carry FMJs in mine, the hollow points just don't penetrate reliably (from what I read from the expertz on the interwebz).
I found these numbers pretty interesting though (interesting in how close they are)...
.25ACP
% of hits that were fatal - 25%
Average number of rounds until incapacitation - 2.2
One-shot-stop % - 30%
9mm
% of hits that were fatal - 24%
Average number of rounds until incapacitation - 2.45
One-shot-stop % - 34%

