The Kel-Tec RDB-C is a semi-automatic bullpup rifle chambered in 5.56x45mm NATO / .223 Remington. The bullpup layout puts the action behind the trigger group, so the 20.5-inch barrel fits into a shorter overall package. Weight is 6.7 lbs unloaded. The downward ejection system makes it genuinely ambidextrous — brass drops straight down rather than to the side. It takes AR-15 magazines and ships with a 10-round magazine. 
 

Key Specifications 

• Model: RDB-C 
• Caliber: 5.56X45MM NATO / .223 Remington 
• Action: Semi-Automatic 
• Capacity: 10 rounds (compatible with AR15 magazines) 
• Barrel Length: 20.5 inches 
• Weight: 6.7 lbs (unloaded) 
• Finish: Black 
   

Features 

The 20.5-inch barrel has a 1:7 RH twist rate, which stabilizes heavier 5.56 projectiles well. No iron sights are included; the Picatinny rail on top accepts whatever optic you prefer. Controls are designed for ambidextrous operation. AR-15 magazine compatibility is useful since those magazines are widely available. 
 

Usage 

The RDB-C is maneuverable at 6.7 lbs and overall shorter than a standard AR-15 with a comparable barrel. It suits range use and home defense scenarios where compactness matters. New users coming from traditional rifle layouts need some familiarization time with the bullpup controls and trigger feel, which is typical of the platform type.

The Kel-Tec RDB-C has a following among bullpup enthusiasts who like its downward ejection system and AR-15 magazine compatibility. Those are its two most-cited practical advantages.

On the positive side: the ambidextrous design gets genuine praise, not just on paper — left-handed shooters appreciate that brass doesn't come at them. Weight and balance are generally described as good for the size. Accuracy with 5.56 is reported as solid at typical ranges.

Reliability feedback is mixed. Most owners have no problems, but there are enough reports of feeding issues with certain ammunition brands that testing different loads before field use is worth doing. Build quality opinions vary — some owners are satisfied, others feel fit and finish don't match the price they paid.

The bullpup trigger is a recurring topic. It's adequate but gets compared unfavorably to a good AR trigger, which is common with bullpup designs. Customization options exist but the aftermarket isn't as developed as for the AR-15 platform.

Kel-Tec customer service experiences are uneven in the community — positive for some, slow or frustrating for others.

Price-wise it's competitive among bullpup rifles. Buyers who go in knowing the bullpup ergonomic tradeoffs and test their ammo tend to be satisfied.