Centurion Arms Harris
The Centurion Arms Harris MARS (Mini Assault Rifle System) is a PDW-style rifle chambered in the proprietary 5.56×30mm cartridge, developed with engineer Mike Harris as a modern resurrection of the 1990s Colt MARS concept. With an 11-inch barrel, 25-inch overall length, and a short-stroke piston system, the MARS achieves approximately 2,600 ft/s muzzle velocity with a 55-grain projectile — carbine-level performance in a package shorter than most subcompact pistol-caliber carbines. The shortened receiver, bolt, and carrier retain the AR-15’s familiar manual of arms throughout.
Read our full Centurion Arms Harris MARS Buying Guide ↓
Harris MARS Specifications
Caliber: 5.56×30mm proprietary. Barrel: 11”. Overall length: 25”. Weight: 5.3 lbs with rear sight. Muzzle velocity: approximately 2,600 ft/s (55g FMJ). Effective range: 300–400 meters. Operating system: short-stroke piston. Battle sight zero: designed for 200m BSZ, trajectory within 3 inches of line of sight. Manual of arms: AR-15 compatible. Action: shortened receiver, bolt, and carrier based on AR-15 platform geometry.
What Is 5.56×30mm?
The 5.56×30mm is a proprietary cartridge developed specifically for the MARS system, using a shortened case to function in the compact action while maintaining the 5.56mm projectile diameter. It achieves high velocity from the 11-inch barrel through high-energy ball powder formulation. The 200-meter battle sight zero keeps the trajectory within 3 inches of line of sight across 0–300 meters, matching the practical engagement envelope of a standard carbine in a dramatically shorter package. Ammunition is purpose-manufactured for the MARS system.
The MARS Concept: Bridging the SMG and Carbine Gap
The MARS addresses a gap that submachine guns and standard carbines both fail to fill. A 9mm SMG is compact but limited to pistol-caliber terminal performance and relatively short effective range. A standard 5.56 carbine with a 14.5–16-inch barrel delivers rifle performance but is difficult to maneuver in confined spaces. The MARS at 25 inches overall with rifle-caliber performance bridges that gap — shorter than a subcompact carbine, more powerful than a submachine gun, with a 300–400 meter effective range that handgun-caliber PCCs cannot match. For vehicle operators, close-protection professionals, and enthusiasts who want a genuinely compact rifle-caliber platform, the MARS occupies unique ground.
MARS vs HK MP5: Compact Platform Compared
The Harris MARS and the HK SP5 (civilian MP5) target similar use cases but from opposite ends of the caliber spectrum. The SP5 fires 9mm from a roller-delayed blowback action in a compact 13.9-inch barrel package; the MARS fires 5.56×30mm from a short-stroke piston in an 11-inch barrel. The MARS delivers higher velocity, flatter trajectory, and greater effective range; the SP5 offers wider ammunition availability and a more established platform with broader accessory support. For buyers who prioritize effective range and rifle-caliber performance in a compact format, the MARS is the stronger technical choice.
Related Pages
See the full Centurion Arms lineup, or browse PDW rifles for comparable compact platforms. Explore AR-15 rifles for standard-format alternatives, and visit pistol-caliber carbines for compact 9mm options.
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