Any ammo is better than none, but the meaning of "range ammo" can vary by use and individual. Pistol rounds are sub-optimal for self defense. Anyone who has reason to think they need a gun and can't be elsewhere (cops, mostly) should be carrying a long gun with which they are proficient. A quality AR with duty ammo is often the best, but in some locales maybe politically ill-advised. A 30-30 or .357 lever gun is a good choice for those places.
As noted by AJ, a .38 WC is often adequate. I generally carry standard velocity SWC .38s in my M66 - the bullet shape is optimal, and it is quite controllable in fast shooting. 9mm FMJ is ... well under optimal, and the wounds are often like the from an ice pick. As noted by Frailer, getting shot with anything is going to suck.
Some important points: One, you must know the parts of the body at which to aim and hit. In crude terms, draw a line between the nipples, then upward lines toward the shoulders, with the upper horizontal line at about the shoulders. Most of the vitals that matter are up there. On the head, a triangle between the outer edges of the eyes and the nostrils. From the side, roughly the ear opening. More access to the CNS, and less bony skull.
In other strings, I have cited to the excellent book by Urey Patrick and John Hall, "In defense of Self and Others ..." Google it. The third edition is the current one. While directed at LE, there are a lot of lessons the rest of us can apply. The 4th chapter discusses ballistic reality. If you do not have and read a copy, you are not intellectually prepared.
The leading authority on ammo performance today, a student of Dr. Fackler, is Dr. Gary Roberts, who is both a trauma dentistry teacher/practitioner, and a cop. Find his testing and pick a round you can get in volume and test for function in your platform.
If you can make the time, the "Primary and Secondary" podcasts are reality based. I think #400 just came out - it is long, but worth it.
Remember this, too: if there is a place or activity that you would not go unarmed, you most likely should not be there armed. I have to go to Tacoma for a training conference later this coming month. I'd rather not be there, but the conference is good and professionally necessary. I'll be carrying a G17 and at least two spare mags.