Securely mounted optics are essential to the accuracy and precision of any rifle. To ensure the new X-Bolt has the most stable mount possible, it features an all new X-Lock scope mounting system that uses four screws per base, replacing the traditional two-screw system. Securing the scope bases at all four corners, rather than only held at the center of the base, allows for more accurate placement of the bases on the rifle's receiver. This revolutionary new X-Lock system holds the base tighter to the rifle than ever before. Requires Browning-style rings. Will not accept Weaver-style or Picatinny-style rings.