As an engraver, I can say you always anneal a case hardened frame, engrave and have re cased. Daryl hit the ol nail on the head re. the 21's. They are as tough as Chinese arithmatic but can be cut ( over an extended period of time & frayed nerves). What type of books are you interested in ? Instructuional or pictorial ? What type of gun are you planing on engraveing ? Give me questions and I'll try and give you answers.
FWIW, Ken


Ken Hurst
910-221-5288