The frizzen above closely resembles the standard Siler frizzen, but has an improved toe position, allowing the frizzen to snap open a bit earlier, speeding lock time. A few Siler kit assemblers try to achieve this same effect by annealing, bending, and grinding, re-hardening and tempering the frizzen spring. This new casting allows you to replace the frizzen, and improve geometry. As cast, you must harden the frizzen after fitting. Drill through the existing frizzen pivot screw hole in your lock plate. Use a hardening compound to harden it.