What about laser-cut acrylic for the butt-stock mounting bracket?
Acrylic is stronger (or less prone to cracking into pieces) than resin. Also, these can be made to be very precise (I use a program that generates .eps files, or Encapsulated Post Script files, which then can be interpreted by a computer to drive the laser cutter), and these files can be made/altered to fit a variety of base pistols, ranging from an actual Webley Flare gun, to a cheapy, $10.00 38 Special from the Hobby Shop... or even scratch-built MDF guns... I just need a a good scanned tracing of the connection point on the pistol grip. Basically, you just remove the woody pistol grip material, and either scan it on an open scanner bed, or trace it to paper, then scan it.
PM me, and I will send my e-mail address for anyone who wants one, to send their .jpg files (or .pdf files).
Another cool point, acrylic can also be painted with a base of grey Krylon Fusion, then painted with a metal-type paint, then weathered.
Later!
Johnny