InRange TV Gives The Kel-Tec RDB A Mudbath… And The Results Ain’t Pretty

The Kel-Tec RDB (Rifle, Downward ejecting, Bullpup) is one of the most promising bullpup designs of recent years, thanks to its slim layout and ambidextrous features. However, there is a lot that can go wrong with even the most clever of designs, and unfortunately Kel-Tec has had a history of producing weapons that, while innovative, have experienced issues with usability, reliability, and quality control. So, the question on many people’s minds was “sure, the design looks good, but can we trust a rifle from Kel-Tec?” InRange TV was one of the recipients of the pre-production RDB, and this week they released their very thorough review of the Kel-Tec RDB, giving us an idea of what to expect:

A brief summary of the video: Karl and Ian were very impressed with the rifle’s handling and ergonomics. One shooter with particularly large hands and gloves who tested the rifle dropped the magazine more than once during the 2-Gun Action Challenge Match, but the general opinion was that the RDB was less susceptible to this problem than its competitor, the Tavor. Karl and Ian found field-stripping to be easy, and swapping the charging handle was easily done with no more disassembly than would be required for routine maintenance. Accuracy left something to be desired; with Eagle Eye 69gr match ammunition, the rifle was printing 5-shot groups between 2.5-3″ in diameter; much wider than a comparable AR would have done. However, as Karl notes, this is not unserviceable accuracy for a duty rifle, just not as good as most AR shooters are used to. Although the gun had modest mechanical accuracy potential, everyone who tested the gun reported an excellent trigger for a bullpup, better than most stock AR-15 triggers.

The mud test brought another flaw to light: The rifle has an exposed ejection chute behind the magazine well that is open to mud and debris. When submerged in mud, the rifle ceases to function as grit totally clogs and blocks both the full rearward travel of the bolt, and positive movement of the hammer. Besides the rifle’s failure in the mud test, Ian and Karl reported good reliability over the course of their shooting.

Despite all this, Ian still called the RDB his favorite bullpup of the current generation.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • JK

    Not a problem, if you can’t find a rifle to submerge in the dirt,anyway.

  • iksnilol

    Hmm, if they made a cover for the chute that opened when the rifle fired and closed itself otherwise it’d be a winner IMO.

    Something like the PKM dust cover.

    • Rocky Chen

      meh i wouldn’t mind having to manually close a cover

      • iksnilol

        21ST CENTURY! We don’t have to settle for not-fancy things for our fancy things. đŸ˜€

    • tts

      Yea have a lever or something trip the dust cover open when the bolt opens and goes back for ejection and put the dust cover on the outside and have it flip up and out to the side of the ejection port. Makes the cover trivial to flip back into position with your hand when you finish firing and you could easily feel for it too.

      Put those external trigger sheet metal extensions on the inside of the receiver too while you’re at it so they can’t get fouled and have the charging handle connected to the piston so you can push the bolt back into position if it gets sticky. Just keep it foldable so it’ll stay out of the way + make the forearm plastic stick out a bit so when the handle reciprocates it won’t hit your hand.

      Would probably survive the mud test easily after doing all that.

      • tts

        Dissassembly also wasn’t bad but I think it’d be better if you could somehow just remove the butt plate and slide out the piston by removing a pin or 2, or better yet a button catch, and flip up the buttstock instead of having to remove 3 pins + the lower to get at the internals which seemed awkward in this and other videos where they took this gun apart.

        These enclosed guns are usually really reliable but when they do jam they seem to be a chore to fix as Ian and Karl noted. You’re pretty much forced to go to your pistol. So anything that made it much easier and quicker to get at the internals would be a big deal to me.

        • Joshua

          the lower actually does hinge open, remove the two rear pins and it folds down on the front pin, whether you can remove the bolt group at that point, it doesn’t look like it. I wonder if the butt plate can’t be removed as a safety precaution, having the butt hard mounted means it is less likely to separate in the event of an OOB detonation, giving your shoulder a little more protection, if it was only hinged and held with a catch it might become shrapnel in that event.

          • tts

            It does hinge open but in a somewhat awkward way. Every review for this gun they end up pulling all 3 pins to get at the action.

            The butt plate looks to just be molded plastic. Perhaps they put in a metal insert for protection but that doesn’t mean it needs to be fixed completely. Just hinge it with 1 fixed pin and have the other removable so it can be popped out and flipped up quickly to pull the action with just a quick yank on the charging handle to pop it out.

    • Sianmink

      Maybe the aftermarket will provide, if Kel-Tec actually makes enough of these things to satisfy demand.
      I’m gonna wait and see how the all-metal M-43 version turns out.

  • Andrew

    Don’t worry, that mud will have already turned to rock by the time Keltec actually produces these.

    • Colin S

      And the rocks would have naturally eroded…

    • Paul O.

      There are a couple on Gunbroker.

      • RocketScientist

        Hey, don’t get in the way of the “Keltc-is-Vaporware” circlejerk. It’s rude to allow actual facts to interrupt these guys.

        • Twilight sparkle

          Try finding one at in at an everyday lgs, gunbroker is fine for people that have an ffl or that know people with an ffl but not everyone has an ffl or knows someone like that.

          • RocketScientist

            Ummmm, there are 2 at one of my local gun shops (a fairly large “chain” with 7 or 8 loc’ns throughout the state). Another, smaller mom and pop place had one in stock last week but it sold a few days back. Both those stores also have/had SU-16 Charlies, SUB-2ks, and PMR 30s on a fairly regular basis. Keltec is a company that makes HUNDREDS OF THOUSANDS of guns a year. It is,as of 2014, the SIXTH LARGEST gun manufacturer in the US. It is objectively false to suggest their guns are impossible to find and that they don’t produce in large quantities. Plus it makes you look silly.

          • Twilight sparkle

            I live near a cablelas and they haven’t been able to get one or at least keep one long enough for me to see, there’s a nice local place called “fun guns” and they don’t plane on trying to get one any time soon and they almost exclusively carry black rifles. I work at a chain that can’t keep pmr 30s in stock but we don’t have trouble with ksgs now. Being the sixth largest in the us isn’t that impressive especially considering how many larger brands aren’t in the us, there’s plenty of guns they have that are easy to find that do seem to be mass produced like the p3at but the newer cooler stuff that people want is vaporware. It’s easier to find a full auto Thompson where I am than it is to find one of these, that should say something.

  • hking

    Wow crappy to hear that the accuracy isn’t there, especially when so many cheap AR barrels can pull 1-2moa.

    • Julio

      The ammunition may be premium, but that doesn’t mean it’s the best match for the gun. With accuracy like that I think they should have done KT the courtesy of testing more than one load before publishing their results.

      • Ian McCollum

        We shot groups with three different types of ammo (Eagle Eye 69r, Wolf 55r, and XM193 55gr) and they all performed the same.

        • Anonymous

          Wolf and XM193 are both 2-3 MOA ammo, at best. You might find a bolt gun that shoots them a bit better, but it’s unlikely. You simply cannot get a rifle to group tighter than the intrinsic consistency of the ammo. Eagle Eye might be awesome stuff, but it doesn’t have the track record of Gold Medal Match. YMMV, but I’ve found very few rifles that won’t shoot FGMM well, if they’ll shoot anything well. And only shooting one grain weight of match ammo, in a caliber that’s rather sensitive to such things, is a definite flaw in the testing.

  • Tom – UK

    Looks like this rifle has great potential, its just a pre-production model after all so lots of room for improvements..

  • Nicks87

    I really want to like bullpups but …

  • TheNotoriousIUD

    So somebody decided to mix crossfit and guns.
    The end times are surely upon us.

    • lowell houser

      2-Gun action match. Start with 3gun, then delete the useless shotgun portion, add calisthenics to increase heart rate, and lots of prone and other ways to get the shooter and gun covered in dust, and structure it all to favor web gear with a useful loadout, and top it all off with the stress of a timer.

  • Cal S.

    I still don’t understand the rationale behind these mud tests. Unless in dire, dire straights I would NEVER pick up a rifle that’s been caked in that much mud before it had been scrubbed clean. Yes, even an AK. Somehow, I don’t feel like having overlooked bore obstructions blowing guns up in my face. Probably just me, though.

    • tts

      Its nice to know that if you really need to use it will work almost no matter what and the instances where you’d really need to use it are the ones where you’ll have no time to clean in properly in the event it ended up caked in dirt.

      Bear in mind, as was mentioned in the video, they’ve similarly caked other guns (like the AR15) in dirt and some still worked fine (like the AR15).

      • Evaris

        They said that similar guns like the AR-15 also failed the mud test, unless I mis-heard something.

        • Some Guy

          They did a previous video doing more or less this same test with an AR, M1A and MAS.

          The AR handled the mud better than the others but it didn’t have zero problems.

        • CommonSense23

          The AR ran half the mag, then had to have the charging handle pulled twice, then finished off the mag.

    • LT

      I hear you Cal – it reminds me of that old joke, “if you are ever being chased by a police dog, don’t weave through some traffic cones, walk a balance beam and then jump through a hoop, because they’re trained for that”.
      I have carried rifles for a couple decades in many environments, and have never had one get caked in mud like that! But then, I’m not a Navy SEAL ™

      • Joshua

        I have. I was never the most graceful person around.

    • James

      If I recall correctly, they absolutely acknowledge this. They state that the test is a worst-case scenarios, the rest of the (fairly lengthy) video is it being tested under more normal conditions, which the rifle performs very well in. They have a very high opinion of the rifle, and simply wanted to see what the worst case is.

    • Cal S., fundamentally, they are evaluating a weapon by finding its failure points. That is the reason for the mud test. “Will it fail?” “Yes.” “Then we learned something.”

  • Shmoe

    That’s a pretty extreme mud test. I would have like to see some sort of control or comparison of another gun in that same (very, very thick) mud. Maybe an AK and/or even a Glock (I would guess the Ak might pass the test).

    All the same, it was the very thorough review I would expect from these guys, lots of useful information! I particularly appreciated the 2-Gun stuff.

  • Cal.Bar

    This thing is NOT ready for prime time. I’ll stick with my TAVOR

  • Evan

    More junk from Kel-Tec. How they remain popular is beyond me. The RDB is an interesting idea, but based on who makes it, I wouldn’t buy one.

    • Cymond

      The word for that is “prejudice”.

      • Evan

        Call it what you will, but I don’t buy products from companies that have a long track record of making junk, especially not major purchases like guns. Kel-Tec makes garbage. Their SU-16 has the dubious distinction of being the worst rifle I’ve ever shot. Not buying anything from Kel-Tec.

  • TDog

    Never did understand the whole “let’s submerge this gun in mud/water/Jell-O thing… most folks never will and if they do, only a moron would sit there and fire it without trying to clean it off first.

    • Dunno if you’ll find puddles of Jell-O anywhere in the world, but at least where I’m from there’s a nontrivial possibility that the rifle could be submerged in mud, if you were out in the field with it.

      It’s nice to know a gun’s limits.

      • TDog

        I challenge any manufacturer out there to say in print, “Submerge my firearm completely in mud and then fire it – I guarantee it will work.”

        No one will say that because only a moron would try it. So if a gun doesn’t work after being completely submerged in Swamp Thing’s rear end, hey, guess what? The world still makes sense.

  • Don Ward

    More like Rifle, DonWard is rejecting!

    • anon

      Well done.

  • Evil13RT

    I think the RDB is a base for future improvements. It needs more attention paid to its disassembly, accuracy, and little things like a dust cover for the ejection port. But all in all its a great first step since its solved the ambidexterity problem of bullpups.

  • Alexandru Ianu

    I can see the point of an extreme test to see the limits of the rifle, but it might be more informative to submerge it in less viscous mud and muddy water, which is way more likely. The most I can see happening in practice with this kind of dense viscous mud is the rifle sitting (floating) on it.

    Anyway, it looks like it’s Kellgren’s best design yet.

  • Jwedel1231

    You brought up the mud test failure, yet conveniently left out the fact that it performed as well as an M-14 would have done. That being said, a cover would be nice and the M-14 isn’t the model of reliability either, but your “summary” was misleading.

  • polarisgold

    Would of been nice to see the rifle without the mud…..

  • Anthony Rosetta

    I’m just not that sold on Kel Tec! But, that’s just me!