Utilizing the USC Upper Side Charging Receiver in combination with the LA-N15 Raven lower this perfectly matched billet receiver set is ideal for new rifle builds in multi calibers. Packed full of features including a broached internally flared magwell, spot face takedown area, ultra smooth proprietary bore, radiused Cam Pin slot, reduced diameter barrel extension area for precise barrel fit, rear set screw lug tensioning & precision machining including reamed holes and single point milled, single operation extension threads.