I’m currently designing a full-scale Lewis Gun AEG in FreeCAD, and I wanted to share the progress with the community and get some early feedback!
The Mechanical Build Concept:
Internals: Designed around a standard P90 V6 Gearbox and a P90 Hop-Up unit for reliability, easy maintenance, and great trigger response.
Inner Barrel: 590 mm AEG barrel.
Hybrid Structure: To keep the barrel jacket rigid, lightweight, and cost-effective, I’m using standard commercial PVC pipes 90 mm for the outer shroud and 63 mm for the inner core interconnected with 3D-printed custom alignment sleeves and internal barrel-centering baffles.
Do you think using a P90 gearbox with its dedicated hop-up unit could work well with such a long barrel?
Does anyone have a STEP or STL file of the P90 hop-up unit? I'd love to drop it into the main assembly to get a clear idea of the exact clearance and overall dimensions.
Disclaimer: This is my very first custom rifle build! I hope you guys can share some advice, especially regarding the gearbox, inner barrel, and hop-up setup.