Systems like the SCAR (Special Operations Forces Combat Assault Rifle) allow caliber swaps in minutes.

Signature reduction is no longer just for "special" missions. Modern tactics emphasize suppressors to preserve shooter communication and hide muzzle flash in night operations. Advances in flow-through technology have reduced the gas blowback that previously plagued suppressed semi-automatic systems.

The standard 5.56x45mm NATO and 9mm Parabellum are being challenged by "intermediate" cartridges designed for better performance through barriers and at longer ranges.

Rounds like the 4.6x30mm (MP7) and 5.7x28mm (P90) offer high velocity and armor penetration in ultra-compact frames. Iconic 21st Century Systems