7×47mm

7×47mm (seven-four-seven) is the standard-issue rifle cartridge of the SDC, meant as a compromise between previous-generation calibres of 5.56, 7.62 and 6.8. A rimless, bottlenecked cased design, the cartridge uses a durable lightweight polymer casing, a solid-block explosive propellant, and comes with multiple bullet types and pressure configurations for filling diverse roles.

Fulfilling both infantry and specialised roles, 7×47mm can be loaded into standard carbines all the way up to long-distance sniper rifles while retaining its extreme effective range and unparalleled stopping power, bested only by its bigger brother, 11×80mm.

7×47mm ammunition has an effective range of 1.55 kilometers with a 5.3 kilometer maximum range. M74 Standard has a velocity of 1.3 kilometers/second. The bullet is designed for minimal loss of energy over distance, greatly reducing bullet drop and dramatically increasing its effective range compared to predecessor cartridges.

Due to its polymer casing and lightweight propellant, 7×47mm is also much lighter than predecessors, with the whole cartridge only weighing 133gr (8.6g) with a 105gr FMJ bullet - almost 80% of the weight of the round is taken up by the bullet only. This does have the minor downside of making the bullet extremely top-heavy, so the primer base is given additional weight to counteract it.

With extremely high velocity compared to 21st century cartridges as well as a relatively heavy bullet, 7×47mm bullets deliver kinetic energy almost equivalent to .338 Lapua Magnum while retaining less than half the cartridge weight and much better ballistic performance.

Performance
7×47mm, compared to the preceding 6.8×51mm cartridge it replaced, possesses a 35% average increase in velocity and much higher effective range, allowing the new ammunition to be loaded and used as sniper ammunition.

7×47mm M74 Standard penetrates from 41 to 47 cm into soft tissue, while penetrating up to 18 mm of steel plating at up to 900 meters. Fragmentation rounds will always yaw and shatter when entering soft tissue, but is unable to penetrate steel plating at standard range.

With high range, stopping power and excellent weight, it forms the standard calibre as a jack-of-all-trades for most infantry roles against enemy infantry or light mechanised infantry, able to be loaded into sniper rifles, assault rifles, and machineguns alike.