GUNBOX-STOCKsmall-13XX

This is just the stock. 
Other parts for this stock are. 
https://www.shapeways.com/product/6P6ZSZFG8/gunbox-railsmall-13xx

Fits my 1322 or 1377 Crossman muilti pump air pistols (relatively new version from the sporting goods store) improving its accuracy as a packable bullpup without the length found in a shoulder stock.

With no real  recoil, its not meant as a shoulder rest. This stock allows you to "grip the back of the stock" using the hollow below your collar bone and your cheek. Improving 1 handed shooting and more natural 2 handed than a pistol grip.

The upper breach screw needs to be replaced with one 1.1875". 

There is a  .3" hole. centered on the  pump cylinder plug for a custom plug with threads or to add some support/stock strength with a steel, aluminum or composite support spar thru the stock. A common carbon fiber arrow can be used glued in place to true up the stock, adds stiffness, reduces heat warping and strength as a spine for the stock.