|These fit 3" .410 shells perfectly (with the rim up). I bought these to tidy up my slugs and buckshot rounds because the little boxes clutter my ammo cans.
I can fit six of these into a .50 BMG ammo box. It's not very space efficient but it REALLY tidies things up, so I'm happy.
There are similar boxes that have a smoother profile (no protruding latch or hinge) but I had trouble fitting .410 shells into those at the store.|