I have uploaded few files which I have been using in last few years you can Download the STL /STEP/M3F files and start building your speargun on CNC or modifying them .
Roller speargun design
https://www.cgtrader.com/produ…argun-spear-length-140-cm
classic speargun design https://www.cgtrader.com/produ…pear-trigger-ermesub-back
Handle design
https://www.cgtrader.com/produ…cb-41cf-ac1d-4efefd1899b5
https://www.cgtrader.com/products/speargun-handle-left
https://www.cgtrader.com/products/speargun-handle
https://www.cgtrader.com/products/left-hand-speargun-handle
https://www.cgtrader.com/products/speargun-line-guide
https://www.cgtrader.com/produ…e2-429c-8fad-0ca6820e02f7
https://www.cgtrader.com/products/trigger-line-release