The issue with most .32 ACP ammo is usually the bullet. An FMJ seen in a lot of ammo, like the Geco (that has less MV and energy than other brands), is mostly useless. A Silvertip, on the other hand, isn't. Even though they're about the same ballistically.
You may wish to bring Canada into the late 20th century in terms of terminal handgun ballistics. Energy doesn't mean squat except as fuel to do work, and the only work of interest for a self-defense handgun is destroying biological tissue in your target. According to the IWBA, the minimum criterion for handgun wounding effectiveness is 12.5 inches of penetration in calibrated, bare, 10% ballistic gelatin. The FBI backs off to 12.0 inches of penetration being sufficient in this tissue simulant medium. I'll stick with the scientists' recommendation of 12.5 inches. I'm not aware of the FBI ever explaining their weaker criterion, but I suspect it is attributable to bureaucratic politics rather than reason.
Once the penetration criterion is met, a bigger hole is better, and a bigger hole can be obtained in two ways -- with a larger diameter bullet, or with a bullet design that reliably expands. But, penetration is the single most important factor in handgun effectiveness.
Per Brass Fetcher (
http://www.brassfetcher.com/Ballistic Gelatin Tests/32 ACP 10 Percent Ballistic Gelatin.html), here are average penetrations and expansions for various commercial .32 Auto cartridges:
- Cor-Bon 60-gr JHP, 1,015 ft/s (all velocities are at impact, 10 ft from the muzzle), 9.8 inches penetration, 0.195 square inch expansion (unexpanded cross-sectional area is 0.076 square inch) -- failed penetration, great expansion.
- Speer 60-gr Gold Dot JHP, 843 ft/s, 7.2 inches penetration, 0.194 square inches expansion -- failed penetration, great expansion.
- Winchester 60-gr Silvertip JHP, 812 ft/s, 11.4 inches penetration, 0.076 square inches expansion -- failed penetration, no expansion.
- Fiocchi 73-gr FMJ, 724 ft/s, 13.4 inches penetration, 0.076 square inch expansion -- good penetration, no expansion.
For a premium price you can carry Silvertips, JHPs that don't expand and fail to adequately penetrate -- an expensive recipe for disaster. Or, you can carry a cheaper FMJ that obviously won't penetrate, but will likely put two superficial wounds into the bad guy -- an entrance and an exit wound -- on each pull of the trigger. If you insist on paying a premium price for .32 Auto carry ammo, Buffalo-Bore HCFN was mentioned above -- virtually guaranteed thorough ventilation of the bad guy with each trigger pull (providing you hit the target).
I'm unaware of any JHP in .32 Auto that will meet the IWBA or FBI penetration criteria, especially out of the barrel of a mouse gun. With such a gun you are already handicapped by having a smaller bullet diameter (presumably for the valid desire for deep concealment); why handicap yourself further by using a round that will not reliably penetrate sufficiently to destroy vital tissues?
If you do insist on carrying a JHP in this caliber, consider confining your shots to the abdomen, where no bones can stop or deflect a shot and cause penetration to be even more shallow. The organ tissues may not be as vascularized as those found in the thorax, but if your assailant does deal you a death blow after you empty your mag into his belly, you can die with the satisfaction of knowing that he may well die a painful death in time.