One problem with having two different rounds is that most rifles won't zero the same with different ammo. Another problem would be that you wouldn't know what round you had loaded next. What if you were only able to get one shot off at a Taliban fighter crouching behind a truck bed and the round you fired didn't penetrate because it broke apart? That would suck.
Federal Tactical is a hollow point. It's what we use at work.
The reason why the rounds recommended are 55 grain is because that's also the weight of most training ammo. That way your training ammo and defense ammo will both shoot close enough to each other that it doesn't make a difference at training ranges.