KelTec RDB Defender – The Gritty Details

With all the goodies for testing.

KelTec has just blessed our FFL with another famously different design, the RBD Defender. The new model is billed as a mash-up of the best features of the RDB Survival and the original RDB, making for an all-purpose, lightweight, bull pup blaster. Like everything KelTec, there are some unique approaches. That famous mix of engineering marvel and sometimes complete disregard for aesthetics, which usually plays out in their favor.

Let’s start with, the RDB Defender is a unique bull pup that retails at an MSRP of $1300. So I don’t expect Cabot Guns level fit and finish, and neither should you. That being said, the RBD Defender has a lot going for it. At 6.7 pounds, it is on the light side for sure. An all polymer body will do that for you. The Defender comes with an aluminum MLOK compatible fore-end, so no stress about attaching lights, lasers, or slings. And as a bull pup, it crams a 16-inch barrel into an overall length of 27 inches.

New MLOK forend.

The barrel has a pencil profile, which contributes to the lack of weight. It does come at a price though. It heats up quickly, which is not unexpected. But considering this was not meant to be mounted on a tripod to defend the perimeter from the Mongolian Horde, it does just fine. The barrel comes capped with an A2 style flash hider, which also means it could be suppressed easily. The adjustable gas block would also lend itself to this conclusion.

The charging handle is a nice large size and is located almost at the end of the handguard. It is easy to grip, and reminiscent of an MP5 in operation. Oh, except the RBD locks to the rear on an empty magazine. Slap the charging handle down to put the bolt back into the battery, and you are off to the races.

Accutac Bipod on a bullpup, a first for this author.

The safety is a weird duck if you are accustomed to ARs. Safe is down, and fire is straight forward. But an angled (Ambi) safety lever makes it so it feels the same as an AR. Press down to shoot, and up to safety. It looks weird, but it works and should offer no shenanigans to AR-trained shooters.

KelTec bills the RDB trigger as unparalleled, which we will assume for niceties only applies to bullpups. And they are correct, bullpup triggers are notoriously bad. Much like trying to change gears on a stick shift rear engine VW bus, there is a lot of linkage by necessity. The Defender trigger breaks at around 6 pounds, with just a little bit of play in it. While this is laughable compared to a high-end AR trigger, I do concede it is very nice for a bullpup. Dry firing the RDB sounds like hitting a piece of sheet metal with a sledgehammer, but it does get the job done. Reliability was high, so I’m not faulting it for the noise.

Trijicon MRO HD and 3x magnifier

Speaking of sheet metal, next up is the magazine release. Now this one fits the strange choices category a little bit. The magazine release does, in fact, look like it was stamped out of a sheet of 16th-inch auto-body steel. In fact, the part you are supposed to grab has clearly been plasty dipped. And while I am no slave to aesthetics, this one has even me a little miffed. But it does work, and solidly ejects empty mags, so I can’t really be that upset. And it also isn’t lost on me that it is so large as to be impossible to miss. Just above the magazine release is a manual bolt lock, for clearing your weapon. It does not, however, release the bolt. This button is one way only. Not a problem, but something to know.

RDB performed admirably at CQB drills

Pulling up the rear (literally) is the adjustable buttstock. First looking at the RBD, I at first assumed you had to adjust the length of pull with tools. Not the case, there is just no way to lock the buttstock in the closed position. It will fire closed, and pressing it into your shoulder should keep it that way. But don’t go looking for a release button to extend it. Just grab it and pull. Which leads to the second bit of function over looks. The buttstock is retained in the open position by an angled piece of sheet metal, spring loaded into place. So there is about an 8th of an inch of play between pulled all the way out, and pressure applied to the stock. Which you don’t notice when shooting, but it is there. Is this actually worse than the little plastic bit that retains a 6 position AR stock in place? Probably not. But it certainly defies convention.

Accuracy was better than expected.

All in all, I find the RDB Defender to be a fine gun for certain applications. As a backpack gun, it is fabulous. Compact, light, and it stows easily in a bag. As a home defender, it is also A-okay in my book. The short length overall lends itself to being a good nightstand gun. Would it be my first choice to take back to Tal Afar? No, but KelTec also didn’t intend it for that. For the money, and the purpose, this is the little blaster that could.








20 or any AR15 Magazine













MSRP: $1000

Click HERE to visit KelTec’s RDB page

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About the author: Clay Martin is a former Marine and Green Beret, retiring out of 3rd Special Forces Group. He is a multi-decade and -service sniper, as well as 3-Gun competitor and Master ranked shooter in USPSA Production. In addition to writing about guns, he is the author of “Last Son of The War God,” a novel about shooting people that deserve it. You can also follow him on twitter, @offthe_res or his website,

{ 12 comments… add one }
  • Paul June 15, 2021, 3:18 am

    I can tell that some people don’t like Kel-Tec, but I have a few that I really like. I bought a P3AT and PF9, and they seemed to work fine, when I shot them. I decided to do some work on them, such as replacing the trigger on the PF9, with an adjustable trigger. I decided to smooth out the machine marks on the slide rails, and and other surfaces, such as all of the steel small parts. I had those parts hard chromed, along with the magazines, then reassembled both guns. I turned the factory sights on the PF9, into fiber optic sights, for added contrast. These guns are Very light weight, and great for an extra pocket gun, and while they won’t replace my Glocks, I have had Zero malfunctions with my Kel-Tecs. I’ve done a few more pairs of the PF9 and P3AT, for my co-workers, and family members, after they shot my Kel-tecs. If you buy these guns 2nd hand, you can get really good prices on them, and after some simple work and hard chrome, they’re better than new.

  • GERALD SCHLENZ June 14, 2021, 3:29 pm

    This reminds me of the Bushmaster bullpup of the 1990s. I like the bullpup configuration. It’s great for handling while getting in and out of a vehicle. My Bushmaster has some drawbacks, too, like limited options for mounting sights. It’s not recommended for disassembly beyond removing the bolt for cleaning. It had a horrible trigger until I sent it in for a repair. It came back with a pretty darn nice trigger pull (shows they can do it when they want to?). The Bushmaster is handy, accurate, and has some AR controls and uses AR mags. This type of carbine definitely has it’s place, especially as a vehicle weapon. At about $600 1990 dollars, it was really comparable in price to the KelTec.

  • David June 14, 2021, 1:28 pm

    Clay Martin thank you very much for your service to our country.

    I liked and agree with most all of your review on this KelTec RDB type bull pup.

    I have been born and raised in what is now behind enemy lines in California and I have been shooting guns since 1971 and collecting guns since 1973 when I was seven and I hope that Judge B. manages to get all of our gun rights of the second amendment and our constitution restored to all of us.

    I’ve had a green KelTec RDB-C which was built specifically for California as a non AR, AR for many years now.

    It’s got a 20 inch barrel with a 1 in 7 twist on it so it’s really very accurate and this RDC tested is a sister to if.

    It dose not have a pistol grip on it so that it can be a spotting rifle in California like a Mini 14, it has a Remington style push button safety, the mag release and bolt release are a little different with a different front hand guard which isn’t as good as this one but works very well for the most part.

    I’ve shot it with all different types and kinds/ brands of ammunition and magazines and it has worked flawlessly.

    I’ve actually hit large concrete targets with it at 1,160 yards that are about the size of the bed of a pickup truck.

    I’ve never been to an indoor range other than shooting machine guns in Vegas. I live on the high desert of Southern California where there are unbelievable amounts of wide open desert spaces to shoot at unbelievable ranges.
    I used to shoot 1,000 yard sillowet with the West End gun club in the early 1980’s so I’ve been used to shooting long range stuff.

    My RDB-C is a truck gun, it fits into a case made for a Mossberg Cruiser pistol griped shotgun so it takes up very little room. I’ve got it set up for my wife for the most part in her Jeep but I would definitely run it if the need arises.
    It has a light laser set up with a HolloSun dot and back up iron sites on it, it’s better than any pistol out there for most all applications.
    My wife is a fairly good shot and has shooting for 37 years since she meet me. She has a Glock 19, but she can actually hit stuff almost all of the time with an AR or the KelTec RDB-C and hitting stuff is what really matters.

    It’s a good all around truck gun and it will do the job but it would be way down on my list of guns to take back to Afghanistan as well.

    I wanted to include a few pictures of my set up on it, but I don’t think that I can share them, sharing is caring.

    I would definitely recommend it for a truck gun application because having anything is better than nothing and for quick defensive actions it would work out very well.

    I’m a collector and have all kinds of stuff from 1886 Lebel’s to AR’s, an AK, M1 Garand’s and so on that I would definitely be more than willing to run in defensive and combat applications if the need arose, so basically I’m just saying that I’d run just about anything if the need arises to defend myself, my family, friends, stuff and country and the KelTec is a good choice to fit into a need that could happen.

    I’ve been a Mechanic most of my life and guns are just like tools that you need to know how to use and know what tool is the right one for which application.

    Good luck have fun shooting, support our constitutional rights and respect and support our veterans, and thanks again to all of our veterans who happen to read this for their service to our country along with all real first responders.

  • survivor50 June 14, 2021, 12:03 pm

    OK… it’s KELTEC.
    We’re used to some funky looking, oddly weird weapons, but this takes the CAKE !
    An UN-AR Bullpup, with nearly AR controls, except in a different place, different shape, and operating different too ???

    If you go full bore ALIEN STYLE… OK, I’m good with that, but at least we shouldn’t need a manual and anatomy chart to fire this thing. Granted, this is the red headed freckled faced bastard child of the “Planet of the Apes, RDB Survival Bullpup, so it’s a BABY step up… wake me when you get to ” ONE GIANT LEAP ” !

    One wonders… What’s the point ??? And CHEESE WHIZ !!! It still cost a bundle… for what it is…

    • Godfrey Washington June 21, 2021, 8:26 am

      Another RDBC owner here, love mine! It works as rifle still considering putting the pistol grip back end on it tho…

  • OldOutdoorsGuy June 14, 2021, 11:06 am

    You do a very confusing gun critique in that you complain about different points as “personal feeling” and then you reverse your negative opinion with a defense concerning the model and type of firearm it happens to be to infer that all those points are really positive points for this weapon? My question to you is, why do you always feel that your opinion is the “positive” side of an issue and the maker’s opinion, if it is available is always negative to the weapon? I feel that they must have had SOME reason for manufacturing the components of the weapon as they did. It may have been to keep the weight to a minimum, it may have been easier to set up the manufacturing tooling, it sure WASN’T to keep the price down, IMHO!!

    Maybe some shooters feel that function may be more important than “fit and finish”. Granted, many of the points in your critique, bolt lock, “sheet metal” controls, barrel type and size, and including “fit and finish” probably aren’t positives for a thousand dollar weapon, but neither are the mysterious addition of a bipod for prone test firing or the lack of any adjustment to compensate for the addition of regular relief scopes or other sight enhancers, and for certain, not for takedown pins which are NOT retained but come completely out to field strip the weapon when needed!! It was evident that the 2 pins, which you did remove completely, suddenly began to roll and disappeared off camera. You offered no acceptable remedy for dealing with loose pins which, in my book, would be totally unacceptable, again, in a thousand dollar weapon which only will accept light grain bullets to be accurate, another negative point not addressed to my satisfaction or to many other shooters I’ll bet.

    Finally, your reference to the term “battle rifle” is as relevant to the review as “assault” or “combat” weapon would be. It just simply isn’t necessary, most of your readers are out of kindergarten by now and don’t need to have word usage “spelled out” for them. Most gun owners, in this day and age, are well aware of what most of the usual “Social”-ist terms mean and don’t need to be reminded of them.

    In conclusion, as a former P-9 owner, I judge most Kel-tec weapons by my experiences with this trade-in from about 20 years ago. That little “mouse” gun had a long trigger creep, a ultra small grip area, and had too many FTE’s for me to keep it very long. That was one man’s experience with Kel-tec and not indicative of any sort of gun “review” whatsoever. But, after shooting my assortment of Sigs during the same period, I was very biased in what I looked for in an EDC weapon.

    Some of my Sigs had problems but, as a matter of fact, I probably carry my Taurus PT-709 Slim more than any other weapon I own. there are far better weapons out there but, for a person who is on just over a grand a month Social Insecurity income since early 2000’s, it is what it is for me. It is light, easy to handle and shoot, and will kill anything or anyone within a 25′ range. That is my “comfort” zone in which I try to verbalize my wishes before the final trigger squeeze takes place. To date, I have only reached that point in which I considered actually shooting the apparent threat once, and that instance ended when the intruder dropped his weapon and ran. [The “weapon”, BTW, was an old “Skandi” type knife, the edge of which looked like he had used it to cut out mag. release levers for bullpup rifles!]

  • Evan June 14, 2021, 10:33 am

    It’s a Kel-Tec. That tells me enough: unnecessarily weird design, poorly constructed out of cheap materials, zero quality control. Hard pass.

  • Russell June 14, 2021, 9:45 am

    Another well written and insightful review by Clay Martin. Clay’s writing style is entertaining and informing. I was so impressed with his writing after reading a previous review, I immediately ordered a copy of his latest book. I look forward to reading it! Bravo Clay!!

  • noncompliant June 14, 2021, 6:58 am

    Kel-Tec has carved a niche for itself in the firearms market. While not appealing to most gun snobs, the products are functional and innovative. No cookie cutter , it has to look like something else, here, and that has earned them a following. George Kellgren has surprised the arms industry and continues to do so. Personally, if I could have one each of their products, I’d be a happy camper. Now, if I could just get my hands on one of their bayonets…

  • Rob F June 14, 2021, 6:18 am

    Clay Martin, thank you for your Service in the Marines.

  • Charles Beck June 14, 2021, 6:16 am

    Well done review. Gave me what I needed up to firing the gun myself. Would like to see a rating system in the future for comparison purposes…ie: A-F or 1 to 10.

  • JUNKDETECTOR June 14, 2021, 4:28 am

    Typical Kel-tec crap. Why even waste a review on this junk? Fortunately, video shows the true nature of Kel-tec – unreliable plastic trash.

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