MAC Takes A Look Inside The Kel-Tec RDB

    George Kellgren is certainly one of the most inventive small arms designers alive today, although his company Kel-Tec has unfortunately become known for their QC troubles and availability problems more than how inspired the designs are. The latest offering from Kel-Tec is no less inventive than previous designs; it is an intermediate-caliber bullpup designed to eject brass downwards, away from the shooter’s face, while being as simple as possible. The way this is done is perhaps better seen than read, so below is embedded a video of Tim from the Military Arms Channel taking a first look at this unique rifle:

    The first thing of note is the rifle’s unusual fire control group. A long hammer mounted at the very rear of the receiver allows rounds to pass through the gun’s downward facing ejection port during ejection, while still giving clearance for the hammer to build sufficient momentum to strike the round’s primer. The bolt group is a simple seven-lug Stoner-Johnson-esque unit (though derived vs. the AR-15; it uses a different profile) with the extractor located at the 6 o’clock position, and two ejectors to give the cartridges the requisite velocity to make it out of the chute at the rear of the receiver. The bolt carrier uses a simple fixed oprod connecting it to a short stroke piston of some variety, probably a short, fast-moving tappet similar to an AUG or FN SCAR.


    A promotional photo showing the RDB’s mechanism. Note the hammer and spring connector bar, in yellow. Image source:

    At the risk of editorializing somewhat, the RDB’s design is one of the most well-though-out bullpups to be released in years, in this author’s opinion. This isn’t to say the rifle is the “end all be all bullpup”, but rather that its basic mechanism is the work of careful creative thought that elegantly solves the problem of ambidexterity in bullpup designs without adding excess weight and cost. There are a couple of potential problem areas, however. The first is the exposed operating rod, which reciprocates visibly over the front handguard housing. This is a very lightweight arrangement, but depending on the details of its construction could potentially cause problems when debris makes it way into that area, if it interferes with the oprod’s cycle. However, that area may also be clear enough for it to not be a problem, only testing will tell. Kel-Tec has also used a magazine release design similar to that of the IWI Tavor – which in the Israeli rifle is reportedly sensitive to accidental release.

    2015-10-19 01_37_36-New Kel-Tec RDB Bullpup - YouTube

    The RDB field strips fairly simply, though unconventionally even by bullpup standards.

    Does the RDB offer enough improvement to finally allow bullpups to make major inroads in the tactical rifle market? It’s difficult to know, but the RDB’s unique and simple mechanism certainly provides a good foundation for a solid product.

    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. He can be reached via email at [email protected]