Well, Mr. Pond, James Pond - I'll try to help (or hurt, as the case may be). Given the conditions that you must use non-hollowpoints, and I'll assume that would normally mean using full metal jacket, I will argue that is an argument actually in favor of .380 acp from a full length (3.6 inch) barrel. In fmj, and in that barrel length, .380 will penetrate enough without over-penetrating too much. 9mm fmj, on the other hand, in many cases would over-penetrate, passing through the target and, therefore, wasting much of its greater energy. Both of them will produce a .355 caliber hole, so it would seem the desired effect is optimal penetration, not energy or expansion. The Sig 232 with fmj gives you that. It has enough power without having too much power for the fmj round used.
I actually believe, without evidence, that is why .380 was so popular among police and civilians in Europe for so long and 9mm was so popular for military use; because before hollowpoints became available 380 acp fmj gave optimum penetration for civilian use in cities without dangers of excessive over-penetration.
I used to own a 232SL and miss it. Hop to get another one day. The Sig is a gem.
Use it up. Wear it out. Make it do, or do without.