The great "what ammo" question!
For years, my answer has been "whatever rounds(factory) I find on top of my dresser". Now, thanks to competition among ammo companies, you can buy ammo specifically tailored for short barrel revolvers such as the 135 gr. HP CCI Gold Dot. Remington, Winchester and Federal as well as CORBON, Black Hills and Hornady all have excellent loads for short barrels.
I'll use any of them but now I at least take time to take the five rounds from the same box. Right now, my every day M42 has the Gold Dots in it. But I have, already pre packed, a box of Hornady and CORBON in my airline lockable case along with my S&W M642.
You might ask why not the others? I use them as well but for airline travel some brands pack 20 or 25 to the box cutting down on weight and giving me more room for other calibers.
Good multiple hits are what is important. Choose ammo which allows you to do this.