It depends on a few things such as velocity and weight, but 50 yards is a good general rule of thumb. Semi wadcutters perform far better at long distances, and I have shot hard cast SWCs at targets hundreds of yards out, walking the shots in, using a spotter. There are actually some loading techniques that aid in producing better results when it comes to long distance handgunning.
Here is a pic of shooting a 5" Model 29 out to (I think) 450 or 500 yards. It was a dry reservoir bed and we lined up pieces of wood about every 50 yards past 300 yards or so. RJM1952 was with me, and we were calling each others shots.
And this is Horse Heaven pass on Idaho's Pahsimeroi Valley of Elmer Keith fame. RJM and I were doing some LR shooting there as well. Plus I have done a good bit of Jackrabbit/varmint handgunning there over the years.
And here is E. Keith a long, long time ago at the same place.
I will occaisionally use full wadcutters in my .44s, and with the wide, full caliber meplat definitely puts a smack down on pretty much anything it hits.
With the .38 Special It is probably the single most effective style of projectile for deep, straight penetration. It also does a heck of a job on small game. I have popped a
lot of jacks using .38 Wadcutters and it definitely does a number on them.
If you want to get good with a J Frame, use one for small game hunting.
Hope some of this is useful if not at least entertaining.