The above link will give you some really good information on the different calibers you have mentioned.
As far as I'm concerned I will take a .38 over either the .32, or the .22. All three calibers will stop a threat, but the question is when? If a person is threatening my life I want him stopped NOW, not later! We all know that shot placement is everyting, but under stress, and possibily under fire, how well do you really think you can place those shots? Most experts tell us that the .380 is smallest caliber to be considered for SD, and I agree with them.
Y'all be safe now, ya hear!
Without God we have no moral compass. Without Family we have no purpose. Without Guns we can not defend either our religious choice, or our family! Millwright