The Ageira Technologies XV-15 is a compact, magazine-fed, closed-or-open bolt, electronic impulse, electromagnet-assisted, delayed blowback-operated automatic rifle employing the high-velocity 6x28mm caseless round, intended to supplement handguns as a backup weapon carried by support personnel in a defensive role or for special operations teams in a niche offensive role. Additionally, with the use of specially-coated subsonic ammunition and a sound suppressor, it can be used in clandestine special operations missions to spoof station sensors and avoid setting off automated alarm systems.

The XV-15 operates on an electronic impulse, delayed-blowback closed-or-open bolt action, feeding from specialized 50-round stick magazines that store rounds perpendicular to the bore axis similar in design to the P90's stick magazine. Essentially, the feed lips of the magazine are attached to a gate that rotates 90 degrees, placing the next round along the bore axis and allowing the bolt to carry the round into battery. In open bolt mode, the advanced primer ignition system uses an electronic impulse to fire the primer very briefly before the bolt actually goes into battery, which normally requires precise timing based on different ammunition types to maximize efficiency. However, a rechargeable lithium-ion battery located inside the "magazine well" powers an electromagnet as well as the firing pin, which compensates for different recoil forces and ensures perfect operation of the mechanism. To use the more accurate closed bolt system, the operator must insert the magazine and hit the bolt release paddle, which will push the round into battery but not fire it. It will then operate normally. Due to the nature of the system, the rate of fire can be tuned via a recessed dial underneath the battery, from 300 RPM up to 1,100 RPM.

The system itself reduces recoil forces compared to a regular straight blowback system, and special compensators and buffers in the stock serve to reduce the recoil even further to manageable levels. Surprisingly, the weapon only has two fire modes: safe, and full-auto. There is no semi-automatic function, although this is compensated by the tuneable rate of fire and the fact that the weapon is not capable of bump-firing or other accidental discharges common to open bolt designs due to the requirement of a full electronic impulse input from the battery and firing mechanism.

For amenities, the XV-15 features an ambidextrous fire selector, magazine release, and bolt catch, ammunition counter, 6-position skeletonized buttstock, and a fully-customizable handguard with 4 modular rail units. The design is fully modular, and can accept a variety of sights, stocks, grips, and other accessories, as well as longer or shorter barrels.

In the event that the weapon overheats, the magazine will half-eject, the bolt will automatically lock forwards, and the ejection port will open. The weapon has an integrated temperature sensor that seizes the action in the event that an ammunition cook-off is imminent. The ejection port can be manually operated and unlocked by means of the ambidextrous charging handle, which is used to chamber a round but is otherwise non-reciprocating. When closed, the weapon's internals are fully sealed. A ambidextrous bolt-release paddle allows the operator to close the bolt and safe the weapon, as well as operate it from the closed bolt.

The XV-15 is entirely made from special stamped temperature-resistant alloys, with most parts made from high-grade polymers and alloys for durability and longevity. The result of this is a rather lightweight platform, at roughly 3 kilograms fully loaded (6.7 kg in XV-15/2 configuration) with a 50-round magazine, but also one that is intensely durable and can withstand all types of environments and pressures. There are two main types of ammunition used in the XV-15, both produced by Ageira Technologies.

A 4.6mm sub-caliber penetrator encased in a cup sabot, designated as the Mark 31 Mod. 0 High-Velocity Armor-Piercing, Sabot round. As the projectile is smaller in diameter and lighter than a conventional round, it is propelled at a higher velocity of roughly 1200 m/s when fired out of 10.3-inch barrel, and the reduced cross section of the penetrator makes it more effective against hard armor. Terminal effects are lessened, although this round is more intended for use against more armored targets such as thin-skinned vehicles or exosuits instead of a standard dismounted infantry unit. HVAP-S rounds are marked with black tips, and weapons firing HVAP-S rounds must have their barrels outfitted with a stellite liner to avoid damaging the rifling with the plastic cup sabot. HVAP penetration is quantified as ~60mm RHA at 45-degree angle from 100m, ~34mm RHA at 45-degree angle from 500m, and ~27mm RHA at 45-degree angle from 1000m.

The standard 137-grain boattail Mark 30 Mod. 0 High-Explosive, Incendiary, Armor-Piercing round is composed of incendiary mix, zirconium powder, HE mix, and a depleted uranium penetrator inside a steel cup, all encased in a copper jacket. It is designed to defeat most common forms of body armor and explode inside the target, with a pyrotechnical detonation train instead of a manual fuse that sets off the HE filler and incendiary mix, to ensure maximum effect and terminal ballistic consistency. Fired from a 10.3-inch unsuppressed barrel, the Mk 30 round generates muzzle velocities of over 900 m/s, with an effective range of 700 meters. AP-I/HE rounds are marked with green tips.

The initial impact of the round ignites the incendiary material in the tip, triggering the detonation of the HE charge. The second (zirconium powder) incendiary charge will also ignite. This burns at a very high temperature, is not easily extinguished, and can last up to 15 minutes. The remaining element of the round is the depleted uranium penetrator. This has a large amount of kinetic energy and will penetrate the armor as solid-cored armor-piercing shot would. This will take the incendiary material and about 20 steel fragments (created by the explosives), delivering them in a 25–30 degree cone through the armor, increasing lethality. Penetration values for HE-I/AP are quantified as ~45mm RHA at 45-degree angle from 100m, out to ~11mm RHA at 45-degree angle at 1000m..