ModLock Ammo Box System Gen 1 | Modular Secure Fit

This is a modular, 3D-printable ammo box system designed for secure storage and transport in range bags, cases, and backpacks. ModLock Gen 1 includes handgun and rifle-size boxes, each using caliber-specific inserts that drop into a shared outer shell.

Every box features a hinged lid and a fully printable snap-in clasp—no hardware required.

Caliber Compatibility & Capacity

Handgun Size

• .45 ACP – 50 rounds (base size for the system)
• 9mm / .380 – 72 rounds
• .22 LR – 171 rounds

Rifle Size

• .223 / 5.56 – 72 rounds
• .350 Legend – 72 rounds
• 12 Gauge – 18 shells

Each caliber uses a dedicated insert sized specifically for that cartridge while sharing the same external box footprint within its size category.

Hinged Lid & Clasp Design

• Hinged lid is a press-fit install and designed to stay upright once opened
• Clasp is fully printable and snaps into the front of the box

• Tight tolerances are intentional to prevent the box from opening while being jostled in a range bag

  

Clasp installation:
Place the clasp on a flat, hard surface and push the lid straight down onto the clasp to snap it into place.

The clasp will be stiff at first by design. Opening and closing it a few times will smooth the action while keeping a secure hold.

Print Profiles & Labeling

Two print profiles are included:

• Standard profile – clean, unmarked lids are included with the full profile
• Labeled profile – lids include embossed caliber names for easy identification are included in a secondary AMS required profile

The labeled version is created directly in Bambu Studio, allowing clear, readable text without modifying the base model files.

Design Notes

• Built for real-world range use
• Modular insert system allows for future caliber expansion
• Tight press-fit components prioritize retention and durability
• Boxes stack cleanly and store efficiently