Snaplock 223/556/300 BLK Ammo Box + Expanding Tray

Updated version of my expanding ammo trays for .223 Rem / 5.56 NATO / 300 AAC BLK

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

Update 2026-05-17: Alternative stackers

Check out these stackers if your collection of boxes is growing: https://makerworld.com/en/models/2815670-ammo-box-stackers#profileId-3134704

Lots of filament but will make you live so much easier.

Update v2 (2026-03-20):

Improved the hinge design for stability during operation. Added a hole for a piece of filament to keep the hinge aligned. Changed the face design across all my models for the aesthetics of the original Snaplock look. Overall more symmetric and looks better when you have a bunch of these stacked next to each other.

Fat fingered people rejoice!

Yeah, I have fat fingers. I don't like wasted space either. But I have to compromise when most ammo storage solutions that are compact and take up less space make it difficult to pull the rounds out of the trays. 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.

Design features:

• Store your ammo in a tight and compact package
• Expand the rows to get your fat fingers in there for easy extraction
• You can easily store bullets primer up or primer down
• Trays are easily removable.
• Latches and be customized in the slicer with caliber and bullet weight text
• Inner label is larger allowing more text.
• Pouch behind inner label to store original manufacturer packaging like LOT numbers or load details.
• Trays are compatible with my earlier design and can be used in either box.
• These Snaplock boxes will stack on top of the original boxes.

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.

Added the 100 round version:

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

The box height was meticulously calculated to allow clearance for the bullet while minimizing the height of the bottom to allow a better grip to remove the inner expanding tray:

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.

Check out the other pistol and rifle calibers in this collection: