What does the Number After the X Mean on Metric Cartridges?

Like this channel? Want it to keep expanding with cool new content? You can make that happen by supporting it via:
Patreon: https://www.patreon.com/MikeB128
Bitcoin: 3JCMNAhrw6Q35CtYS17YD4QYQJg6rdvcTw
MERCH: https://www.mikesmilitaria.com/collections/youtube-merch

Also, if you like Military Surplus gear and collectibles, visit my online store HERE: www.mikesmilitaria.com