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Kel-Tec RDB Rifle Review: The Budget Bullpup with 1 Special Feature

Kel-TEC RDB Rifle
Kel-TEC RDB Rifle. Image: Creative Commons.

Kel-Tec RDB Rifle Is Special for 1 Reason: With the notable exception of the German-designed MP35 machine pistol in the 1930s, most early compact small arms have been designed with right-handed shooters in mind. For decades south paws had to simply deal with bullets ejecting across their face. In recent years there have been attempts to produce ambidextrous designs, notably the IWI Tavor and Steyr AUG – but those required that the shooter physically swap the bolt and extractor, and even required special parts.

The Kel-Tec RDB – as in “Rifle, Downward-ejection, Bullpup – is a truly compact firearm that features a completely ambidextrous design. It utilizes a rotary bolt with a spring-loaded ejector with a downward-facing extractor. The result is that spent shell casings are ejected downward through the stock and behind the magwell.

The compact rifle features a bullpup configuration, which passes the magazine in the stock. This isn’t exactly a revolutionary concept in 2021; rather Kel-Tec’s design is actually quite evolutionary, building on the Steyr AUG, FN 2000 and SA80 while offering notable improvements.

This includes a gas regulator that is built into the Barrel Assembly Group, which can allow the shooter to adjust the amount of gas used to cycle the action; while the bolt utilized dual ejectors to assist in positive ejection. This feature also allows shooters to tailor the bolt carrier speed to eliminate excessive recoil – such as when using a suppressor or to ensure reliability for various loads. Moreover, while it is unlikely that someone would ever need to fire the rifle upside down, it could still be done.

The RDB, which fires from a closed bolt, also features a non-reciprocating charging handle that has been described as being similar to the HK MP5 in its function. It can be pulled back and rotated upward to lock the bolt open, then pushed downward to load the cartridge. Although it isn’t actually necessary, the charging handle can be swapped from left to right during disassembly.

The RDB series of semi-automatic bullpups are chambered for 5.56x45mm NATO, and currently includes four models. The standard RDB model for the U.S. market is the RDB-17, which features a 17.2-inch barrel with 1/7 twist. It features a high-impact resistant Zytel forend with built-in Picatinny-style rail on the bottom for mounting accessories.

The RDB Defender is a lightweight version that is features an aluminum, M-LOK handguard, collapsible stock and 16-inch barrel; while the RDB Hunter features a traditional style assembly rather than pistol grip to house the trigger and cross bolt safety – and also includes a swivel stud bipod mount, along with 20-inch threaded barrel. The RDB Survival is the smallest and lightest of the lineup, and according to Kel-Tec was designed for use in the back country, providing center fire rifle power in a compact and lightweight package. The Survival features a 16-inch lightweight barrel, folding sights and collapsible stock.

The MSRP for the RDB17 is $1,000 – less than half the current price for the Steyr AUG A3 M1. For the budget-minded who want something different, Kel-Tec hits the bull’s eye.

Peter Suciu is a Michigan-based writer who has contributed to more than four dozen magazines, newspapers and websites. He regularly writes about military small arms, and is the author of several books on military headgear including A Gallery of Military Headdress, which is available on

Written By

Peter Suciu is a Michigan-based writer who has contributed to more than four dozen magazines, newspapers and websites. He is the author of several books on military headgear including A Gallery of Military Headdress, which is available on Suciu is also a contributing writer for Forbes Magazine.



  1. Whynotthinkwhynot

    December 7, 2021 at 10:39 am

    I own an RDB. It is a good weapon, great design, but I have some warnings for future owners. First off, complete disassembly, and removal of factory grease from the gas piston is a must. Be sure to use a lube on the piston that will withstand combustion temps or the gas adjuster will not function for long. Secondly, proper Loctite for small screws must be applied to every external screw .ie rail, cheek guard. There aren’t many screws to do, but I ended up losing a cheek guard screw in the field because I didn’t do that. Third- pay close attention to where the action rod seats in the buttstock. There is a small divot it must fit into or you could have ejection issues. 4- The gas action rod spring, if you remove it, please note that it is not reversible! If you put it back together ant it easily fits into the gas tube- push the rod into the tube by hand. Note that there is a lot of resistance near the end of the rods travel. Remove, reverse the spring, it will be difficult to fit the spring on the rod and in the tube. It will only seat properly if you get the spring started in the tube and on the rod, then use the rod to force the spring in the tube. Now push the rod in, and the rod travels freely without the spring binding in the tube. Improper installation of this spring will result in ejection jams where a spent case lodges in the action. That’s it!! The RDB is not perfect, but it’s a good weapon if properly maintained and lubricated. I could make recommendations…. But that’s not the scope of this comment. Happy days in many ways to you all!!

  2. Richard Hardesty

    December 7, 2021 at 4:46 pm

    No mention of Ket-Tec using FNH technology. The P90 and civilian PS90 later both use technology of downward ejection, ambidextrous design. Not a word in this article about them. Disappointing! Ket-Tec recently developed a pistol using the same 50 round magazine from the P90/PS90 using the 5×7 small caliber rifle bullet. Seems like some credit should be given to FNH but sadly wasn’t.

  3. Jeff

    December 8, 2021 at 10:54 am

    Thanks for the details of ownership and proper maintenance and assembly of the RDB. I’ve been waiting for an RDV Defender to show up at a reasonable price and this is very helpful!

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