Short answer: a fitted case for 25 shells of 12 gauge 2-3/4" is about 109 x 194 x 78 mm (4.3 x 7.6 x 3.1 in); 3" shells need about 6 mm more height. Twenty-five 20 gauge shells fit in about 100 x 178 x 78 mm (3.9 x 7.0 x 3.1 in). Store shells cool and dry - paper hulls swell in humidity - and keep birdshot, buckshot and slugs in separate, labelled blocks.
Shell dimensions that set the case size
A 12 gauge shell has a rim of about 22.8 mm; 20 gauge is about 20.6 mm. A 2-3/4" shell is about 70 mm long and a 3" shell about 76 mm. Each shell stands upright in its own pocket: rim + 0.6 mm, with 1.6 mm walls between pockets.
Shotgun shell case sizes
| Holds | Hinged lid (mm) | Slide-off lid (mm) | Printed as |
|---|---|---|---|
| 25 x 12 ga 2-3/4" | 109 x 194 x 78 | 111 x 184 x 80 | one plate |
| 25 x 12 ga 3" | 109 x 194 x 84 | 111 x 184 x 86 | one plate |
| 50 x 12 ga 2-3/4" | 234 x 169 x 78 | 161 x 234 x 80 | two parts |
| 25 x 20 ga 2-3/4" | 100 x 178 x 78 | 102 x 168 x 80 | one plate |
A 50-shell 12 gauge case is printed in two parts because base and lid together do not fit one print plate.
Standing up or lying down?
Standing shells upright in pockets is the easiest way to count and grab them, and it keeps crimps from being crushed. It also lets you see at a glance which pockets are empty.
Keep shells dry
Plastic hulls handle humidity well; paper hulls swell and can stick in a chamber if they get damp. Store shells in a dry place, and add desiccant if your storage spot is ever humid.
Sort by load
Birdshot, buckshot and slugs look the same from the top. Keep each load in its own block or case and label the lid - our lid marking can print "12 GA / SLUGS" or anything else you choose, in a second color.
Build a shell case in the case builder - mix gauges, shell lengths and gear like chokes in one case.
Frequently asked questions
How big is a 25-round 12 gauge shell case?
About 109 x 194 x 78 mm (4.3 x 7.6 x 3.1 in) with a hinged lid.
Do 3 inch shells need a bigger case?
Only a little taller: about 6 mm more height than 2-3/4" shells. The footprint is the same.
How big is a 20 gauge shell case for 25 shells?
About 100 x 178 x 78 mm (3.9 x 7.0 x 3.1 in).
Should shotgun shells be stored upright?
Upright in pockets is easiest to count and grab and protects the crimps; lying flat is fine in a box.
Do shotgun shells go bad in humidity?
Paper hulls can swell when damp. Plastic hulls cope better, but keep all shells cool and dry.