Fellow in the UK has a pair of books out that outline the process.
Howard Buckley, IIRC, is his name. The first book is a walkthrough of building the mechanism for a standard type of airgun as seen in the Brit market, Precharged Pneumatic, single shot. I've read through the book, but don't own a copy. The second book is apparently more oriented towards a airgun along the lines of the Air Force Talon type, using a paintball CO2 or compressed Nitrogen tank for the motive power.
DAGS and find. "The Modern Pneumatic Airgun" by H.M. Buckley.
Cheers
Trev
