Upgrade your ergonomics with this fully parametric length-of-pull (LOP) extender for the Magpul CTR / MOE carbine stocks. This design isn't just a solid block; it features an integrated honeycomb internal structure and a recessed locking lip to ensure your factory rubber buttpad stays securely seated under recoil.

🛠 Features

• Integrated Recoil Lip: Features a custom-fit rim that "nests" the original Magpul rubber pad, preventing it from shifting or rotating.
• Honeycomb Core: Engineered with an internal hexagonal grid to maximise rigidity while significantly reducing filament use and weight.
• Parametric Design: Optimised for a standard 25mm (1-inch) extension, but easily adjustable via the provided OpenSCAD script.
• Duty-Grade Walls: Thick 4mm outer shell for impact resistance and durability in the field.

🖨 Print Settings

For maximum strength and safety, use the following specifications:

• Material: PETG, ASA, or ABS (Highly recommended for impact resistance). Use TPU (95A) if you want a semi-flexible "spacer" feel.
• Wall Loops: 4–6 (Critical for screw hole integrity).
• Top/Bottom Layers: 5 (Ensures a solid mounting surface).
• Orientation: Print with the Stock Interface side down (no supports required).
• Infill: The honeycomb is modelled into the geometry, so you can set your slicer infill to 0% or a low percentage to fill any minor gaps.

🔩 Required Hardware

Since you are extending the length of the stock, you will need longer screws to reach the internal brass inserts of the CTR:

• Screw Type: #10-24 Machine Screws (Flat Head).
• Length: Your chosen extension_depth + 15mm (approx. 5/8").
  • Example: For the standard 25mm extension, use 1.75" or 2" screws.

⚠️ Safety & Fitment

• Verify Fit: This is designed specifically for the Magpul CTR/MOE profile. Ensure your screws have at least 6mm of thread engagement into the stock before firing.
• Calibration: If the fit is too tight, a light sanding on the inner lip or a 1% scale increase in your slicer will provide a perfect "click" fit.