box magazine

noun

a rectangular cartridge holder in a submachine or light machine gun.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for box magazine

Historical Examples of box magazine

They were modern weapons,--the new high power 30-40 box-magazine rifle, shooting government ammunition,--and had been used.
The Mystery
Stewart Edward White and Samuel Hopkins Adams