The Kel-Tec RDB is a bullpup semi-automatic rifle in 5.56mm NATO / .223 Remington. The bullpup layout puts the action behind the trigger group, so you get a 20.5" barrel in a package only 30.4" long and 6.9 lbs. The receiver is 4140 steel. It runs a fully adjustable gas piston system that handles a range of ammunition reliably. Twist rate is 1-in-7, which stabilizes heavier projectiles well. Picatinny rails are present front and rear for optics and accessories. The downward-ejecting system makes it fully ambidextrous — no brass in the face for left-handed shooters. Comes standard in OD Green with a lever safety and accepts standard STANAG magazines at 30-round capacity. 
 

Key Specifications 

• Manufacturer: Kel-Tec 
• Model: RDB 
• Type: Modern Sporting Rifle 
• Caliber: 5.56mm NATO / .223 Remington 
• Barrel Length: 20.5 inches 
• Total Length: 30.4 inches 
• Weight: 6.9 lbs (110.4 oz) 
• Capacity: 30 rounds (compatible with standard magazines) 
• Safety Mechanism: Lever safety 
• Finish Color: OD Green 
• Receiver Material: 4140 Steel 
   

Features 

The adjustable piston can be tuned for different loads without tools. The downward ejection port is the standout mechanical feature — it eliminates the traditional left-hand problem entirely. Picatinny rails at front and rear give optics mounting flexibility.

Feedback on the Kel-Tec RDB tends to split pretty clearly between what the design gets right and where it falls short.

The compact bullpup layout is the main draw. Owners regularly note that getting a 20.5" barrel into a 30.4" package is a meaningful advantage for home defense and transport, and the 6.9 lb weight is easy to carry over long periods. The downward ejection system gets specific praise from left-handed shooters who can run it without modification. Ergonomics and the way it shoulders are generally well-received.

Reliability with certain ammunition is the most common complaint. Some owners report feeding failures or jams, which is a real concern if the rifle is intended for defensive use. The trigger pull is heavier and less refined than what you find on AR-15s at similar prices, and it comes up enough that aftermarket trigger upgrades are a common suggestion. Accessory selection is narrower than the AR platform, which limits customization options. Opinions on aesthetics vary — the bullpup shape appeals to some and puts others off.

Net sentiment leans positive among shooters who specifically want a compact 5.56 bullpup, but the reliability and trigger concerns are worth knowing going in.