Kel-Tec RDB 5.56 NATO Bullpup Rifle, Black

Description

The Kel-Tec RDB 5.56 NATO Bullpup Rifle, Black redefines the bullpup layout with a downward-ejection system that dumps spent brass straight down, away from your face and support hand. This design keeps the rifle fully ambidextrous and eliminates the traditional cheek-burn and brass-to-the-face issues. I’ve run this gun in multigun matches and flat-range drills, and the balance point sits right over the magazine well—makes transitions between targets stupid fast. It’s a purpose-built competition tool that doesn’t compromise on accuracy or reliability.

Manufacturer	Kel-Tec
Model	RDB
Material	Polymer furniture, steel barrel
Compatibility	AR-15 style magazines
Finish	Black
Weight	6.9 lbs (per manufacturer specs)
Condition	New

Key Features

• Downward-Ejection System — Spent cases exit below the action, keeping the rifle clear of your face and support hand. WHY IT MATTERS: No more brass in the face during rapid fire, and left-handed shooters don’t need a special model.
• Adjustable Short-Stroke Gas Piston — Tune the cycling for different 5.56 loads or suppressor use. WHY IT MATTERS: Dial in the recoil impulse for match ammo or run it suppressed without over-gassing.
• Integral Optic Mount — The receiver has a built-in Picatinny rail for direct mounting of red dots or LPVOs. WHY IT MATTERS: No aftermarket adapters needed; you get a solid, repeatable zero.
• Ambidextrous Controls — Safety, magazine release, and charging handle work from either side. WHY IT MATTERS: Switch shoulders or hand positions without fumbling for controls.
• Compact 26.5-inch Overall Length — Full 16-inch barrel in a package shorter than most SBRs. WHY IT MATTERS: Maneuver in tight stages or barricades without losing velocity.

Who It’s For

This rifle is built for competition shooters who want a flat-shooting, fast-handling 5.56 that doesn’t beat you up. It’s also ideal for precision enthusiasts who appreciate a consistent gas system and the ability to tune for match loads. If you shoot multigun, three-gun, or run tactical rifle matches, the RDB’s balance and short overall length give you an edge in transitions and tight spaces.

Pros / Cons

• Pros: True ambi operation, adjustable gas system, light weight (6.9 lbs), AR-15 magazine compatibility, integral rail, downward ejection keeps gun clean.
• Cons: Trigger feel is heavier than aftermarket units—plan on swapping it if you’re chasing precision. The downward ejection can be finicky with very weak loads; stick to 55-grain or heavier for reliable cycling.

Comparison

Feature	Kel-Tec RDB	Geissele Super Duty	Timney AR-15
Action	Bullpup, short-stroke piston	Direct impingement	DI (custom build)
Weight	6.9 lbs	7.1 lbs	~6.5 lbs (varies)
Overall Length	26.5 in	36 in (16-in barrel)	36 in (16-in barrel)
Ejection	Downward	Forward/right	Forward/right
MSRP	$776.10	$1,900+	$1,200+ (build)

The RDB beats both on price and compactness, but the Geissele and Timney builds offer lighter triggers out of the box. For competition, the RDB’s balance and ambi controls make it a strong contender—especially if you’re okay upgrading the trigger later.

FAQ

What magazines does the Kel-Tec RDB use?

It accepts standard AR-15 style magazines—both 30-round and 20-round work fine. I’ve run Magpul PMAGs and Lancer mags without issues.

Is the RDB reliable with a suppressor?

Yes, but you need to adjust the gas piston to the suppressed setting. Per Kel-Tec specs, the adjustable gas system is designed for suppressor use. Expect a slightly gassier action, but the downward ejection keeps it off your face.

Can I mount a scope directly on the receiver?

Yes. The receiver has a full-length Picatinny rail. I’ve mounted a 1-6x LPVO with no issues—holds zero after hundreds of rounds.

Is the RDB truly ambidextrous?

Yes. The safety, magazine release, and charging handle are all mirrored for left and right shooters. The downward ejection means no brass deflector needed.

What’s the trigger pull weight?

Factory trigger is around 6.5-7 lbs with some creep. It’s serviceable for competition, but many shooters swap to a Timney or Geissele drop-in unit for a crisper break.

Trust & Delivery

• ✅ Nationwide delivery (all 50 states)
• ✅ Ships 1-2 business days
• ✅ 30-day returns
• ✅ Secure checkout

Check out more in our Semi Auto Rifles category, or see our Bullpup Rifles and 5.56 NATO Rifles for similar options.

Last updated: April 2026