Is 32 ACP Good For Self-defense?
32 ACP was popular for self-defense. 32 ACP guns are considered too small for ‘proper’ self-defense by some people. Many personal-defense professionals suggest that the 9 mm is the minimum caliber, while some concede to using it. 380 ACP for a deep cover or pocket pistol.

Table-3-CENTERFIRE-PISTOL-DATA
.25 ACP 155.0 dB
.32 LONG 152.4 dB
.32 ACP 153.5 dB
0.38 157.7 dB
9mm 159.8 dB