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The Kel-Tec RDB Defender .223/5.56 AR-15 rifle brings bullpup ergonomics and modern tactical features into a compact, lightweight package built for serious shooters who want maneuverability without compromise. At just 6.7 pounds unloaded, this black rifle cuts down on fatigue during long days on the range, in the field, or on your property—yet it doesn't sacrifice the ballistics or reliability you expect from a 5.56 platform. The RDB Defender merges proven Kel-Tec design with thoughtful details: a collapsible stock that lets you dial in your length of pull, a 16.1-inch barrel tuned for a 1:7 twist (standard for heavier .223 loads), and an aluminum M-LOK handguard ready for lights, lasers, or other gear.
Bullpups aren't for everyone, but they excel in tight spaces—whether you're navigating urban terrain, dense timber, or the interior of a vehicle. The RDB Defender's overall length of 27 inches keeps things nimble in those scenarios while the 16.1-inch barrel maintains velocity and sight radius. The rifle cycles reliably with any standard AR-15 magazine (30-round or otherwise), so ammunition logistics aren't a headache. A smooth 4.5 to 5.5-pound trigger breaks cleanly, making accurate follow-up shots manageable across skill levels.
This is Kel-Tec's answer to shooters who've outgrown entry-level bullpups but want to stay lean and agile. Whether you're building a home-defense rifle, stocking a ranch, or exploring the tactical rifle space for the first time, the RDB Defender delivers versatility and handling that punches well above its weight class.
| Caliber | .223 Rem / 5.56 NATO |
| Barrel Length | 16.1 inches |
| Overall Length | 27 inches |
| Twist Rate | 1 in 7 inches |
| Weight (Unloaded) | 6.7 lbs |
| Magazine Capacity | 30 rounds (accepts any standard AR-15 magazine) |
| Trigger Pull | 4.5 – 5.5 lbs |
| Stock | Collapsible |
| Handguard | Aluminum M-LOK |
| Finish | Black |
Yes. The RDB Defender accepts any standard AR-15 magazine and ships configured for 30-round capacity, so you can run whatever platform-standard mags you already have in your armory.
The bullpup layout moves the action rearward, keeping the overall length down to 27 inches without sacrificing barrel length or ballistic performance. That compact footprint makes it easier to maneuver through hallways, doorways, tight brush, or confined vehicle interiors—all practical advantages when speed and control matter most.
The aluminum M-LOK handguard provides multiple mounting points for lights, lasers, foregrips, and other accessories. The flat-top Picatinny rail on the upper receiver is standard for red-dot sights or magnified optics.
A 1:7 twist is a fast, versatile twist rate that stabilizes heavier .223/5.56 projectiles—including 75 to 77-grain rounds popular with long-range shooters—while still handling standard 55 to 62-grain loads without issue. You'll have broad ammunition compatibility across the .223/5.56 spectrum.


SKU: 120913732 • Width: 10.5in • Height: 3.8in • Depth: 37in • Weight: 10oz