See the ammo orracle on combloc ammo.
The short answer for 5.56mm is, yes - bimetal jacketed FMJs fragment poorly if at all. However the 62gr JHP bimetal comblock ammo generally does much better. Personally, I would consider the czech M193 bimetal FMJ to be just like any other bimetal FMJ (poor) unless proven otherwise by documented testing. Good for blasting.