Kel-Tec RDB
The Kel-Tec RDB is a 5.56 NATO bullpup rifle that solves the problem that has plagued the bullpup design for decades: brass ejection into the shooter’s face. By ejecting spent cases downward through the bottom of the stock rather than to the side, the RDB is genuinely ambidextrous — left-handed and right-handed shooters both get the same experience with no modification required. Combined with a 17” or 20” barrel in an overall package shorter than a 16” carbine, the RDB delivers rifle velocity in a maneuverable format that the standard AR-15 simply can’t match for size.
Read our full Kel-Tec RDB Buying Guide ↓
The Downward Ejection System: Why It Changes Everything
Traditional bullpup rifles like the Steyr AUG and Tavor eject brass to the right — which means left-handed shooters get hot brass across their face on every shot. Converting them for left-handed use requires either expensive conversion kits or factory left-hand models. The RDB’s downward ejection feeds spent cases through a chute in the stock that exits below the trigger guard. The shooter’s face is never in the ejection path regardless of which shoulder the rifle is shouldered on. This single design decision makes the RDB the most genuinely ambidextrous bullpup available at any price point.
Ballistics Advantage of Bullpup Configuration
A bullpup places the action and magazine behind the trigger, which means the barrel can be longer than an equivalent overall-length conventional rifle. The RDB in its 17” barrel configuration is shorter overall than a 16” AR-15 carbine — while delivering significantly more muzzle velocity from the longer barrel. 5.56 NATO gains roughly 25–30 fps per inch of barrel, so the RDB’s 17” barrel produces meaningfully better terminal ballistics and trajectory than a 16” M4-profile AR. For tactical or hunting applications where both compactness and velocity matter, bullpup geometry offers a genuine advantage.
AR-15 Magazine Compatibility
The RDB accepts standard AR-15 STANAG magazines — a deliberate design choice that eliminates the proprietary magazine problem that hampered earlier bullpups. Any AR-15 magazine you already own — PMAG, Lancer, aluminum GI — drops directly into the RDB. This is a significant logistical advantage for shooters who are already invested in AR-15 magazines, and it means the RDB’s magazine supply is the most readily available and affordable of any bullpup on the market. Kel-Tec made the right call prioritizing compatibility over a proprietary system.
Trigger Quality in a Bullpup
Bullpup triggers have historically been a weak point — the long linkage between the trigger shoe and the action introduces slack, creep, and inconsistency. The RDB’s trigger is better than most bullpups at its price point, with a manageable pull weight and reasonable reset for a bullpup design. It won’t satisfy shooters accustomed to match-grade AR triggers, but it’s adequate for field use and significantly better than the Tavor’s stock trigger. Aftermarket trigger improvement options are emerging as the RDB’s user base grows.
Who the RDB Is Right For
The RDB makes the most sense for left-handed shooters who want a bullpup without brass-in-face compromise, for shooters who want a compact 5.56 package with full rifle-length ballistics, and for buyers who want something genuinely different from the standard AR-15 without abandoning AR-15 magazine compatibility. It’s also worth considering for home defense where a shorter overall length is a priority — the RDB’s compact footprint handles better in confined spaces than a standard rifle-length AR.
Related Pages at Impact Guns
See the full Kel-Tec lineup including the Sub-2000 and P15. For AR-15 comparisons browse our AR-15 rifles page. For 5.56/.223 ammunition see our .223/5.56 ammo page.