Snaplock 338 Lapua Mag. Ammo Box + Expanding Tray

Updated version of my expanding ammo trays for 338 Lapua Magnum

… now with a Snaplock box for more secure transport. The original model can be found here. 

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This expanding holder lets you store and transport your ammo in compact form factor while giving you the flexibility to expand the trays for easier loading and unloading.

Updated to v2 - 2026-03-20:

Improved the hinge for stability during operation. Added a hole to insert a piece of filament which will keep the hinge aligned. Updated the face for aesthetics and symmetry. The picture above don't show the bullet image on the lid but it is there in the print profile. Forgot to color it before printing.

Design features:

• Store your ammo in a tight and compact package
• Expand the rows to get your fingers in there for easy extraction
• You can easily store bullets primer up or primer down, but rifle cartridges are best primer down.
• Trays are easily removable.
• Latches can be customized in the slicer with caliber and bullet weight text
• Inner label is larger allowing more text.
• Room behind inner label to store original manufacturer packaging like LOT numbers and load details.
• Stacking ring is compatible across all calibers in this system

 

Stacking ring is optional if you don't need that feature. Or glue them in place on the bottoms:

The stacking rings are compatible across all calibers (large and small boxes stack).

 

Inner label lets you store original packaging details like Lot Numbers or powder charges.

Membership

If you wish to sell print of this model, join for a commercial license.

 

I started with the parametric Snaplock V1 box originally created by @Hugo but have added my own improvements:

Lid height has been meticulously calculated to ensure bullet clearance when opening and closing. The lower height of the bottom and side cutouts make removing the inner trays much easier.

Expanding trays can double as reloading trays:

Compact design allows access to all rows when performing a powder charge on primed cases, unlike bulkier reloading trays that cannot reach all rows:

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Assembling the hinge:

There is a groove on the underside of the hinge on the bottom half of each box. You slide the lid half hinge into those grooves to assemble the hinge. It can be a tight fit, but once you get it started just advance it a small bit on neach side until it drops into place. A piece of filament can then be inserted in the hole of the hinge to keep everything aligned.

Check out my other models in this collection: