Why it matters: The RDB is Kel-Tec's 5.56 bullpup, and it sells at roughly the price of an entry-level AR-15. A creator who has now put three Kel-Tecs on camera says the rifle needed more gas than he first gave it, and that he still did not enjoy running it.
The YouTube channel Administrative Results posted a review of the Kel-Tec RDB Defender on October 16 under the title "Poverty Or Luxury." It is the third Kel-Tec the channel has covered, after the PLR-16 pistol and the SDP. The host says he bought the rifle with channel funds because he had "gotten the Kel-Tec bug" and considered the RDB one of the company's more interesting designs.
The rifle in the video is the Defender version, which has an M-LOK handguard. The host fitted a muzzle device for a Plan B-style suppressor mount, a SureFire forend weapon light, an A3 riser and a Crimson Trace red dot that he says came through OpticsPlanet, the channel's optics sponsor. He fired it both suppressed and unsuppressed, and on camera he takes a face full of suppressor gas from the rifle.
Kel-Tec RDB double feeds and the gas setting fix
Most of the video's shooting was marked by malfunctions. The host describes repeated double feeds, and shows a spent case wedged between the bolt and the wall that divides the magazine well from the ejection port. He says he kept a flathead screwdriver on hand to clear stoppages, and shows a round that came out of one jam damaged. Asked how often the rifle stopped, his camera partner, Colton, answers "pretty often."
The host's diagnosis is that the rifle was under-gassed and the bolt was not cycling far enough. For a final day of filming he turned the adjustable gas regulator up "quite a bit," and says the rifle then had a single malfunction late in the session. He calls the earlier problems "user error." Moments later the rifle stops again, and he says, "Maybe I spoke too soon." He adds that the higher gas setting made the recoil "slightly bit more violent."
RDB bullpup handling: trigger, controls and downward ejection
The host credits the RDB with the strengths bullpups are usually bought for: a 16-inch barrel in a short overall package, a light pencil-profile barrel, and easier handling around barricades. His list of weaknesses is longer. He cites the manual of arms, magazine changes, a bolt release he calls "funky," and a trigger heavy enough that his finger tired during magazine dumps. He describes the recoil impulse as a "chunky" feeling in the face and shoulder, though less pronounced than the 9mm SDP he reviewed earlier.
On the downward ejection he is mixed. He counts it as a plus for left-handed shooters, then notes that rifles such as the Steyr AUG and IWI Tavor offer swappable ejection instead. He also shows four or five spent cases that came to rest in the chest rig he wore while shooting.
He shows the takedown as well, noting that the rifle comes apart by removing three pins that are not retained to the gun, and he mentions that other reviewers have focused on its short-stroke piston system.
“The host turned the gas up for a final day of shooting and called the earlier stoppages user error, then the rifle stopped again.”
J.D. Whitfield, The ReticleIn a 14-round group fired at 100 yards with 55-grain ammunition from Badlands Munitions, the channel's ammunition sponsor, he counts five tight hits and wider dispersion around them. He attributes part of the spread to a hastily built firing position and a rough zero set at about 36 yards, and says he had expected worse.
Kel-Tec RDB price against the AR-15 market
The host frames the rifle with a thesis from the video's title: Kel-Tecs, he says, tend to be either a "poverty purchase," bought by someone who may not know the alternatives, or a "luxury purchase" by a buyer who can afford to take a risk on gear for fun. He puts the RDB in what he calls an "uncanny valley." It works on paper, he says, but about the same money buys an AR-15, and that platform's aftermarket is far deeper.
He sees the RDB's place as a fun gun for the range or for themed matches. He says he considered running it in a Starship Troopers-themed division at a match in Flagstaff, Arizona, but did not. He also mentions truck-gun use as a role some buyers might see for it, and says he does not keep guns in vehicles himself. He says he would not "bank my life" on the rifle, and offers his own view that bullpups appeal most to people who do not shoot or carry a rifle often, pointing to the British L85 and to Israeli forces' use of AR-pattern rifles alongside the Tavor.
He closes with credit for the company. He says he likes Kel-Tec for its willingness to try unusual designs, and that it produces both "an absolute banger" and "some duds." Of the three he has reviewed, he names the PLR-16 his favorite and says the SDP and the RDB did not work out for him. The video also carries sponsor segments for American Pipe Dream and the Sonoran Desert Institute.
For context
- RDB stands for Rifle, Downward-ejection, Bullpup; Kel-Tec's 5.56 design fires from a closed bolt on a short-stroke gas piston and ejects spent cases down behind the magazine well.
- The Defender variant was announced in 2020 with a 16-inch pencil-profile barrel, an aluminum M-LOK handguard and a 6.7-pound weight, at a launch MSRP of $1,072.
- Kel-Tec markets the RDB's adjustable gas piston as a way to tune bolt speed for a suppressor or for different loads, so the right setting varies by setup.
- The Reticle covered the same channel's Kel-Tec PLR-16 review in August.
