SpringGrip - Parametric Cartridge Box, 20 round

📦 Unique Cartridge Box Design 

Unlike generic ammo boxes, this one is built directly on real cartridge dimensions. That means it’s never larger or smaller than it needs to be.

Each round is held securely by four spring‑like fingers, applying gentle pressure. Every finger is integrated with a spring connection to either the box itself or a neighboring finger, adding rigidity and consistency to the grip. This design detail is fully built‑in — no extra assembly or hardware required.

The result is a box that remains forgiving of small variations in cartridge size, printer accuracy, or material shrinkage, while still ensuring reliable retention without rattling, squeezing, or loose fits.

A practical, precise solution for reloaders and makers who value efficiency and smart engineering.

🔧 Modifying the Cartridge Box

To adapt this cartridge box to your desired chambering:

1. Visit CIP – Homologation.
2. Find your cartridge and click FR, EN, or DE to open the CIP drawing in your preferred language.

🖥️ Using MakerWorld Customizer

Once you have the CIP drawing in front of you:

1. Click Customize.
2. Confirm by selecting Customize in the dialog box.
3. MakerWorld’s Customizer will open.

📏 Transferring Dimensions

Copy the following values from the CIP drawing into the corresponding parameters in the Customizer:

• L1, L2, L6, R1, E, P1, P2, H1
• Note: The parameter for L6 is labeled COAL (Cartridge OverAll Length).
  • This is intentional, since many handloaders exceed L6.
  • If you use reloads with longer COAL, enter your maximum COAL instead of the standard L6.

🔩 Bolt Length

The final parameter is the length of the M3 bolts used for the hinge and lock:

• Default length is 30 mm.
• Slightly shorter or longer bolts can also be used.
• If the box is narrower than the desired length, the width will automatically adjust to the maximum possible.

🎨 Preparing in Bambu Studio (or any slicer) 

After downloading from the Customizer, simply click Auto Orient and then Arrange. Add any text, color, or logo you’d like, and set your preferred filament and slicer settings. No supports are required — the model is ready to print as‑is.

🌦️ Filament Choice 

For outdoor use — and to achieve the best spring‑like effect of the fingers — PETG is, in my view, the optimal filament. It combines durability with flexibility. That said, every maker should choose the material that best suits their own needs and preferences.

🛠️ Assembly

Assembly is simple: insert three screws — one in the hinge, one securing the latch, and one for the latch to lock around. Note that the holes on one side are slightly larger than on the other, so ensure the screws are inserted correctly.

📤 Sharing Print Profiles

Please publish print profiles for chamberings that don’t yet have one. This ensures that users on mobile devices can access as many chamberings as possible.

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Walkonwater3D