This mini hybrid in progress has a galvanized steel chamber, aluminum cam locks, and an NPT spark plug. I have pneumatically tested it to 200psi with no leaks, sounds like a firearm when the disk blows. In the third picture, I have included a penny and a writing pen to give you an idea of scale

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I am currently in the process of designing a stock/handle assembly and need help with ideas. The second pic shows my best stock idea.
You can help me out by transferring the first picture to paint and drawing a design for me. Any ideas or suggestions are appreciated. Thanks for the help everyone!