In September 2012, Nighthawk Custom started using only parts that they developed in house. These parts are all fully machined from solid billet. Billet parts are widely known to be much stronger and more reliable than other manufacturing methods, and Nighthawk offers nothing but the highest quality parts to their customers.This new 1-piece Mainspring Housing is the strongest, most robust part of its kind anywhere. It starts as a solid 2 A 1/4" block of steel, the it's then fully CNC machined and checkered to tight tolerances. The butt of the mag well is rounded to reduce printing when carrying concealed. The checkering is 20 lpi to provide a more positive grip.