Been using the MTM ammo cases but they don't necessarily fit well in ammo boxes. Although it is less per box (95 vs 100) it will fit more boxes vertically in a 30 caliber ammo box. I also have an extended model that fits in a 50 cal vertically or in the smaller box horizontally.

Note with the 38 Special, because of the rimmed round put in alternating rounds, there will be a smidge of overlap but the top still goes on fine. If you find some tight, just use an expended round and shove in a couple of times it will ream it out