57 Center LLC is a manufacturer of AR platform rifles. They are located in Bellevue, Washington, USA.
related:
- http://www.57center.com/ ⇒ company website (I think)
- Their guns are listed in the Blue Book of Gun Values.
Footnotes / Sources:
Fjestad, S. P. Blue Book of Gun Values. 32nd. ed., Blue Book Publications, Inc., 2011.