Fragmentation by a handgun bullet is not usually a good thing because of lack of penetration. Penetration is important in reaching vital organs. The most important single factor in penetration is the momentum of a projectile (Mass * Velocity) and NOT kinetic energy (1/2Mass * Velocity*Velocity). As you can see by the formulas, mass of a projectile more directly effects its momentum than its kinetic energy.
Now, in rifle velocities, fragmentation may be a very good thing as there is still enough momentum to penetrate and the kinetic energy is enough that it more reliably creates other damage through hydrostatic shock. Most handgun bullets do not move fast enough to reliably cause tissue damage through hydrostatic shock (some people disagree).
Some manufacturers market handgun bullets specifically designed to fragment or which come pre-fragmented. These are mostly gimmicks. There's a reason law enforcement doesn't use them except in possibly extreme situations.
BTW, to my knowledge, fragmentation is not an issue in Hydra-Shoks.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.
no guns = might makes right