All modern infantry weapons from pistols to assault rifles use micro-scaled mass accelerator technology. Projectiles consist of tiny metal slugs suspended within a mass-reducing field, accelerated by magnetic force to speeds that inflict kinetic damage.
The ammo magazine is a simple block of metal. The gun's internal computer calculates the mass needed to reach the target based on distance, gravity, and atmospheric pressure, then shears off an appropriately sized slug from the block. A single block can supply thousands of rounds, making ammo a non-issue during any engagement.
Top-line weapons also feature smart targeting that allows them to correct for weather and environment. Firing on a target in a howling gale feels the same as it does on a calm day on a practice range. Smart targeting does not mean a bullet will automatically find the mark every time the trigger is pulled; it only makes it easier for the marksman to aim.