I was at Cabella's the other day and stumbled on some ammunition boxes that fit nicely the large size 1876 cartridges. You want the ones that work with .223 WSSM, .270 WSSM, .50-70 government, etc.
Case Gard 50 round flip up box (https://www.cabelas.com/p/mtm-case-gard-50-series-rifle-ammo-boxes?searchTerm=mtm%20case%20gard%20rsld-50)