The Interlock is an old school cup and core bullet with exposed lead tip with a small ring inside the base of the jacket that holds onto the core. They work pretty well, but they are not real high BC bullets. I used to use them 30+ years ago. Not a bad bullet. I have killed a number of pretty good deer with Interlocks.
The Hornady SST is a more modern design plastic tipped, high BC cup and core bullet without a locking ring. They fly really well, and open up really fast. I would hesitate to use them on anything larger than smallish deer (in fact, I wouldn't use them on deer, I prefer penetration over grenades for deer), but I have customers who love them (deer on the coast in WA are pretty small). For a smallish rifle caliber, I would opt for a sturdy bullet, not a violent upset bullet. 30 cal and above they might be fine since you are slinging a pretty heavy chunk of metal.