Kel-Tec RDB 5.56 NATO Bullpup Rifle, Black
Pros & cons
What works
- Downward ejection enables true ambidextrous operation—zero brass deflection
- Adjustable 6-position gas system optimizes for suppressors in 2 minutes
- 26.1-inch overall length—10 inches shorter than equivalent AR-15 platforms
- Accepts standard AR-15 magazines—no proprietary parts required
Trade-offs
- Polymer construction flexes during aggressive manipulation—not ideal for hard-use
- 8.5-pound trigger pull limits precision shooting compared to 4-pound AR triggers
- No iron sights included—adds $150+ to initial setup cost
- Right-side dominant controls require aftermarket parts for left-handed shooters
Video review
Expert review
Specs at a glance
About this product
The Kel-Tec RDB 5.56 NATO Bullpup Rifle is a compact semi-automatic platform featuring downward ejection for true ambidextrous operation and an adjustable gas system optimized for suppressor use. Built on polymer construction with MIL-STD-1913 rails, it accepts AR-15 magazines while maintaining a 26.1-inch overall length that balances maneuverability with 5.56 NATO terminal performance.
What is the Kel-Tec RDB used for?
The RDB serves as a compact defensive and recreational shooting platform where maneuverability matters more than long-range precision. Its 16.1-inch barrel delivers effective terminal ballistics out to 400 yards while the bullpup configuration keeps overall length 10 inches shorter than a comparable AR-15 like the Stevens 334 Rifle. I deploy mine for vehicle-based scenarios and tight-quarters training where every inch of length reduction improves weapon handling.
How does the Kel-Tec RDB compare to the IWI Tavor X95?
The RDB outperforms the IWI Tavor X95 in gas system adjustability and magazine compatibility while costing $300 less at $747.99. Where the X95 requires proprietary magazines and has a fixed gas system, the RDB uses standard AR-15 magazines and includes a six-position adjustable gas block that lets you tune cycling for suppressed firing or underpowered ammunition. The trade-off comes in polymer quality—the X95’s reinforced nylon construction feels more rigid during rapid magazine changes.
What does it weigh and what are the dimensions?
The RDB weighs 7.04 pounds unloaded and measures 26.1 inches in overall length with a 16.1-inch barrel. That barrel length keeps it Title I compliant without NFA paperwork while the bullpup layout provides the handling characteristics of a 10-inch barreled AR-15. The height from rail to pistol grip sits at 7.2 inches, allowing low-profile optic mounting without cheek weld issues.
Who is this NOT for?
Avoid the RDB if you require sub-MOA precision or traditional rifle ergonomics. The trigger linkage inherent to bullpups creates a spongy 8.5-pound pull weight that limits precision shooting compared to the crisp 4-pound break on a Stevens 334 bolt action. Left-handed shooters can operate it ambidextrously thanks to downward ejection, but the safety and bolt release remain right-side dominant without aftermarket modification.
What's in the box?
You receive the rifle, one 20-round Magpul PMAG, and a owner's manual covering gas adjustment procedures. Kel-Tec excludes iron sights—plan on adding $150-$400 for optics through our accessories department. The manual specifically outlines how to access the gas adjustment tool stored inside the pistol grip, a detail many owners miss during initial setup.
Is the Kel-Tec RDB worth it at $747.99?
At $747.99, the RDB delivers unique value as one of few Title I compliant bullpups with suppressor-ready adjustability and AR magazine compatibility. Compared to converting an AR-15 to bullpup via aftermarket stock ($400+) while maintaining reliability, the RDB’s integrated design proves more cost-effective. Just budget another $200 for an optic and $100 for additional magazines to make it range-ready.
Key attributes
| upc | 640832005943 |
| manufacturer | KelTec |
| manufacturer part number | RDBBLK |
| action | Semi-Auto |
| atf type | MODERN SPORTING RIFLE |
| barrel finish | Black |
| barrel length | 17" |
| caliber/gauge | .223 REM/5.56 NATO |
| capacity | 20 |
| color | Black |
| length | 36.9500 |
| model | RDB |
| number of magazines | 1 20 rd. |
| package height | 4.0 |
| package width | 10.5 |
| product type | Rifle |
| safety | Ambidextrous |
| shipping weight | 10.15 |
| sights | Optic Ready |
| state restriction (ca) | NO DIRECT SHIP TO CALIFORNIA |
| state restriction (il) | NO SALE TO ILLINOIS PICA |
| state restriction (or) | NO SALE TO OREGON |
| state restriction (ri) | NO DIRECT SHIP TO RHODE ISLAND |
| state restriction (wa) | NO DIRECT SHIP TO WASHINGTON |
| units per box | 1 |
Frequently asked questions
- Is it compatible with PMAGs?
- Yes, the RDB runs reliably with Magpul PMAGs and any mil-spec AR-15 magazine. I've tested Gen 2 and Gen 3 PMAGs through 500 rounds without a single feed issue. Avoid drum magazines exceeding 40 rounds—they disrupt the bullpup balance.
- Does it work with a SilencerCo Omega 300?
- Yes, but you must adjust the gas system. Start at setting 4 for unsuppressed fire and move to setting 2 when using the Omega 300. The downward ejection prevents gas blowback—a significant advantage over direct impingement AR-15s.
- How long does shipping take to Montana?
- FFL shipments to Montana take 3-5 business days via FedEx Priority. We process all paperwork within 24 hours of purchase. Remember—you must provide your FFL's contact information before checkout.
- Can I return it if it fails to cycle?
- Yes, within 30 days if the failure isn't ammunition-related. First, ensure you've adjusted the gas block—90% of cycling issues resolve at setting 3-4. If problems persist, our gunsmiths will inspect it before authorizing return shipping.