Mad Dog

Its not an "R"for sure. Serial #604155 with no letter designation. It honestly appears as though someone (Gunsmith or Apprentice, Non Factory) drilled and tapped it, i.e. no chamfering. The holes are spaced 1/2" apart both front and back. My real question is Where can I find the prints identifying the radiuses. I am a Tool Maker and have access to CNC 3D machining. Just trying to eliminate set-ups in the mill.

Guess I will just have to wing it the old-fashioned way. I'll figure it out. I'll post pictures once I get done. Waiting on Brownell's now.