The Kel-Tec RDB is a semi-automatic bullpup in 5.56 NATO / .223 Remington with a 17.4-inch barrel at 1:7 twist, 27.4-inch overall length, and 30+1 capacity. It weighs 7 lbs. The finish is black polymer on the chassis with a salt bath nitride receiver. Safety is an ambidextrous dual-action design. 
 

Key Specifications 

• Model: RDB Rifle Downward Ejection Bullpup 
• Caliber: 5.56 NATO / .223 Remington 
• Action: Semi-Automatic 
• Barrel Length: 17.4 inches 
• Overall Length: 27.4 inches 
• Weight: 7 lbs. 
• Capacity: 30+1 rounds (magazine included) 
• Finish: Black Polymer with Salt Bath Nitride Receiver Finish 
• Safety Mechanism: Dual Action Safety (Ambidextrous) 
   

Detailed Features 

The downward ejection system routes spent brass down through the stock behind the magazine well rather than ejecting sideways, which makes the rifle genuinely ambidextrous without cheek weld concerns. At 27.4 inches overall with a 17.4-inch barrel, the bullpup configuration provides a longer barrel in a shorter package than a conventional carbine with the same barrel length. The adjustable gas piston system can be tuned for bolt carrier speed, useful when running suppressed or with varying ammunition loads. The trigger was designed to address common bullpup trigger criticisms with a reduced take-up and cleaner break than most bullpup designs.

The Kel-Tec RDB in black attracts buyers specifically for its bullpup configuration and downward ejection system, and feedback reflects that targeted appeal.

The compact overall length with a full-length barrel is the standout feature in most positive discussions. Owners who need a maneuverable rifle for home defense or who value storage efficiency find the 27.4-inch overall length significant.

The downward ejection draws consistent praise from left-handed shooters, who appreciate being able to use the rifle without brass ejecting toward their face.

Ergonomics are generally described as comfortable, though the bullpup layout has a learning curve for shooters accustomed to conventional rifles.

Reliability reports are more varied than for conventional AR-15s. Some owners run the rifle without issues; others report feeding or cycling problems with certain ammunition. This is more common in early-production units.

The trigger is a mixed topic. Kel-Tec worked to improve on typical bullpup trigger characteristics, and some owners find the result acceptable. Others still consider it the weakest aspect of the design.

Aftermarket support is limited compared to AR-15 platforms. Owners who want to customize beyond the standard configuration find fewer options.