Originally Posted by
commandar
Bonded means that the jacket and lead core are bonded together such that they're less likely to separate after striking a solid object, which generally makes for weight retention and thus better penetration. This will generally make a bonded round more effective after passing through a medium like auto glass on its way to its target.
I'm not familiar with the terminal ballistics of the Tactical Bonded round, so I can't really speak to its effectiveness; for a non-bonded round, the HST tends to perform fairly well in terms of weight retention, however.