Here is a link to ballistic tests done w/ the Keltec. I carry Fiocchi FMJ personally. Best penetration. JHP won't reliably expand in this caliber.
.32 Ballistics Test
Be aware that the Winchester used in this test isn't the same that Wal-Mart now sells. The FMJ Wal-Mart sells NOW is shaped like hollow points - so it could cause rimlock.