I don't know that I totally agree with some of this. I reload for my snubbies, and a +P load with a 125 gr. Gold Dot or XTP, runs across the chrony at better than 1200 fps..
7.0 grs. of Longshot @ 1200+ fps consistently expands and penetrates through and through 16" of tightly rolled up water soaked denim. In fact, I place the water soaked, tightly rolled up denim held together by bailing wire, then place it in a card board box lined with a trash bag, then filled with water. The projectiles pass completely through and leave a very good wound channel. When recovered, the bullets consistently mushroom from .600" to as much as .725", and are fully intact when fired from a 2-1/2' revolver.
.357 mag. is another story. I run H110 / 296 loads. 158 gr. Gold Dots and XTP's from a 2-1/2" revolver are achieving no less than 1250 fps, and penetration is through and through. 158' expansion averages about the same as the .38 spcl. +P 125's. The .357 mag. H110 loads with 125 gr. JHP's are on the edge of 1400 fps., and although penetration is still completely through 16" of denim, expansion is almost all the way to the bottom of the bullet shank, pedaled down past the base. There is some fragmentation, but not a lot with either XTP or Gold Dot.
The factory self defense +P 38 spl. offerings haven't really impressed me. I've run some of the rather expensive stuff, Gold Dots and Hydra Shock 125's across the chrony, and velocity has been a disappointing upper 900's to an occasional 1050 fps. from a 2-1/2" barrel.
GS