Home Depot...
These are great for reloading gear, GO/No GO gauges et al. Range gear etc.
These are the shallow ones... I also own about 40 of the deep ones (they have side tabs to interlock 2 or 3).
I use a color code method... Calibers... (obsolete list)
Also in my shop for Trades...
Ammo cans as well (colored duct tape).