Modular rifles built on chassis, which permit the operator to switch barrels, bolt faces, and magazines in order to change from one cartridge to another, are steadily increasing in popularity among military, law enforcement, competition, and recreational marksman communities. Resultantly, a number of forward-thinking manufacturers have responded by introducing modular rifle systems which are engineered to satisfy the demands of operators of all experience levels. The FN Ballista represents Fabrique Nationale's entry into this rapidly-expanding category. It competes with the likes of the Remington Defense Modular Sniper Rifle ("MSR"). In 2013, the MSR was named as the choice to become the new Precision Sniper Rifle of the U.S. Army and USSOCOM, demonstrating the significance that these organizations seemingly place on the modular system.

An aspect of modular rifles that makes them particularly user-friendly is that changing calibers can be performed very quickly in the field. The Ballista is able to undergo a caliber change (.338 Lapua Mag., .300 Win. Mag., .308 Win.) in less than two minutes. Additionally, the chassis, action, and adjustable trigger (single- or two-stage) of the Ballista have been designed to wring the best performance possible from the premium barrels, all of which measure 26 inches and feature polygonal rifling with a right-hand, constant twist rate.