Compact + Expanding Ammo Storage: Pistol and Rifle

UPDATE January 2026: 

I've published some new models that offer improvements to this design. Please check them out before printing this older design:

Have you ever wondered how to get your ammo out of these super compact storage trays?

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. Well this expanding holder lets you store your load in a compact configuration and then flex it out to allow plenty of room to grab what you need.

Notice: new print profile for faster printing of the ammo trays. These will work with all existing enclosed boxes. Thanks to @Brotaoski for pointing out that straight lines print much faster.

Current calibers:

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 pull out loads that are inserted primer up or primer down
• Two sizes of expansion: Large for wider expansion, Small for tighter fit.
• Ribbed Lids can stack in either direction with inverted text for easy identification
• If you like boxes, we've got one for you. Each print profile has an enclosed ammo box too.

So my original design with the ribbed lids was really just to have something different, but I've since come around to the benefits of having a more stable stacking solution, so I much prefer the enclosed boxes over the lids.

Note: for .357 Magnum, you can use the 9mm shell holder if downloading the STL files directly .

Install Tips:

1. All swivel connectors must be installed in the same direction
2. The orientation of the connector from one row to another matters and will effect the direction of expansion.
   1. Angled upward from left to right is a more natural expansion direction for right-handed folks
   2. If you need to work on your left-handed grip strength, install downward from left to right
3. Use a rubber… mallet to install the swivel pegs. A single thrust of the hammer should do it.
4. Flex the assembled holders a few times to loosen up the action

If you need additional calibers, let me know.

Some images of the companion enclosed stackable boxes with interchangeable labels:

Updates:

2025-06-07: updated all the labels for the new rifle caliber boxes. There was a small error when I copied these files that made the tabs easily break when installing them on the lids.