Since "senior" is in quotes, I am guessing you probably come out of undergrad with a senior title or get it after 1-2 years.

Big4 I used to work are fairly clear about who they call senior (consultant / senior consultant / manager / senior manager/etc) and I can rarely fault them. Now for consultancies (Accenture and the like), the term is a bit more loose indeed.

I'm talking about a fresh out of college grad/undergrad.

Managers charge 400-600(mind you 25% on top of this is for travel).

How much does each level take home? Like if I bill out at $500 an hour are they paying me around 250/hr ~500k/yr?

Not exactly. The thing to keep in mind here though is that billable rate isn't necessarily 40 hours/week and you likely have some sort of salary component that requires you to hit a base amount of billable hours.

So something like (just making up numbers here)

$120,000/year $170/hr for each billable hour over 20 hours/month Sales/delivery bonuses, etc.

That still seems low for any big4. Those were numbers I remember seeing 25 years ago for large consultancies personnel.