Sounds about right. My pack usually weighs that much, including 2L of water. If I'm really strict about every item that goes in there and am able to share a few things with a partner, I can get it down to 25 lb.

My impression is that 27 lbs for 7 days is about average for weight-minded hikers, and a LOT lighter than an average, normal hikers. (My pack used to weigh 40 lb for 3 days...)