Description
I was at the range with a buddy who only shoots traditional ARs when I pulled out the Keltec RDB20, 5.56/.223, 20″ Barrel, 20rd, Tan. The first question was, “What in the world is that?” followed quickly by, “Can I try it?” After a mag, his skepticism turned into genuine interest. That’s the RDB20’s effect—it challenges expectations.
The Keltec RDB20 is a 5.56 NATO/.223 Remington bullpup rifle with a 20-inch barrel, a 20-round magazine capacity, and a distinctive tan finish. It uses a unique downward-ejecting, long-stroke gas piston system housed in its bullpup configuration, offering a full-length barrel in a compact, maneuverable package that ships to Missouri and compliant US states.
Here’s the thing—Keltec doesn’t do boring. The RDB platform’s genius is in its downward ejection. Brass gets spat out the bottom, right behind the magazine well. This makes it completely ambidextrous; there’s no gas or hot brass in your face if you’re a lefty. I’ve put a few hundred rounds of mixed .223 and 5.56 through this model, and the system just works, keeping the action clean. The 20-inch barrel is the standout feature here, giving you all the velocity and ballistic efficiency of a full-size rifle, but in a chassis that’s only about 30 inches overall. That’s shorter than most 16-inch-barreled AR-15s with the stock extended. The weight, at roughly 7.7 pounds unloaded, balances surprisingly well for a bullpup.
The controls have a distinct learning curve if you’re an AR purist. The magazine release is up front, the charging handle is non-reciprocating and on the left side, and the safety is ambidextrous. After a couple of range sessions, it becomes second nature. The trigger is a big talking point. For a bullpup, it’s pretty good—a consistent, two-stage pull that’s far better than the spongy triggers found on many other rifles in this layout. It’s a drop-in ready platform; you take it out, lube it, and head to the range. No gunsmithing required to get it running.
| Caliber | 5.56 NATO / .223 Remington |
| Barrel Length | 20 Inches |
| Overall Length | ~30 Inches |
| Weight (Unloaded) | ~7.7 lbs |
| Magazine Capacity | 20 Rounds (Accepts standard AR-15/M4 magazines) |
| Finish | Tan |
Pros: The compact overall length with a full-power 20-inch barrel is its killer app. True ambidextrous operation thanks to downward ejection is a huge plus. It reliably feeds from any mil-spec compatible AR magazine I’ve tried, from Magpul PMAGs to Okay Industries Surefeeds. The trigger is respectable for the bullpup class.
Cons: Bullpup manual of arms is different—it will feel alien at first. The magazine release location takes deliberate practice. Some find the cheek weld a bit high for certain optics. Field stripping is more involved than an AR-15.
So who is this for? It’s perfect for the shooter who values a compact footprint without sacrificing barrel length and ballistic performance—think truck gun or woods walking. It’s also a fantastic option for left-handed shooters tired of adapting to right-ejecting platforms. If you’re bored of the same old AR and want a functionally innovative, conversation-starting rifle that performs, the RDB20 deserves a hard look. At $1075.54, it sits in a unique niche.
Frequently Asked Questions
Q: What magazines does it use?
A: It uses standard AR-15 pattern magazines. The one it ships with is a 20-rounder, but it will accept any 5.56/.223 AR mag, including 30-round PMAGs and other common brands.
Q: Is the downward ejection reliable, and where does the brass go?
A: In my experience, it’s been very reliable. The brass is ejected forcefully downward and slightly forward, landing a few feet in front of you. It keeps the action cleaner and is a non-issue on most surfaces—just don’t expect to collect your brass easily.
Q: Is it difficult to clean?
A: It’s more involved than a direct-impingement AR. You need to remove the barrel and trigger pack group to fully access the piston system. It’s not hard, but it has a few more steps. Regular field cleaning is straightforward.
If the idea of a compact, full-power, and genuinely ambidextrous rifle intrigues you, check out the Keltec RDB20 in tan, available at firearms-missouri.com for Missouri residents and nationwide.
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