A different design for a revolving rifle, but this one is full auto – and a mystery!

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Ever wanted a revolving rifle that fired three-round bursts at an equivalent cyclic rate of 4,900 rounds per minute? Three inventors in the 1970s came up with an idea to do just that. Maybe.
The revolver mechanism has proven itself over the last century or so to be a robust and reliable means of providing repeating capability to a handgun. Of course not all revolvers have been handguns; there have been a few revolving rifles over the years, none of which were tremendously successful (for several reasons.)

That hasn’t kept inventors from dreaming up new applications, of course. The Firearm Blog this week came up with some pictures and a patent application for a revolving rifle designed to fire three-round bursts. That’s right, a full auto revolver!

The patent, submitted by Robert Magardo, Leonard Ambrosini and Raymond Isenson, details a rifle which fires three rounds in rapid succession from a 3-chambered cylinder (though they note the mechanism could be adapted to fire any number of rounds automatically.) They apparently believed that their concept reduced malfunctions by eliminating a number of reciprocating parts and/or cycles.

While that sounds plausible, I had one little nagging doubt: even if the mechanism didn’t fire and extract in succession, you still need to figure out a way to load, extract, and then reload to keep the next chamber in the cylinder full. That requires reciprocation, and even if it’s not for the round which comes immediately it has to happen sometime.

The inventors had an interesting workaround, or rather two workarounds: first, the mechanism fired three rounds before fully resetting itself. Once three shots were fired the cylinder came to a stop only long enough for those those three chambers to be simultaneously reloaded.

The operating rod, moving backwards under gas pressure from each shot, rotated the cylinder just enough for the next round until it reached the limit of its rearward travel; a spring forced the op-rod forward after those three rounds were fired and at the same time forced three new rounds into their waiting chambers.

But that ignores one little detail: the fired cases need to be extracted somehow, and this is where it gets interesting.

Their second workaround was to apparently use a straight-bored chamber and rimless rounds. The fired cases are described as being ejected forward, pushed out their respective chambers by the incoming ammunition!

Astute readers will see the several potential problems which could arise: first, how do you maintain any sort of headspacing? How do you keep the new rounds from sliding forward and the firing pin not reaching the primers? How much force will be needed to push out the brass (which, as any revolver shooter knows, sometimes sticks in the chamber and needs a solid shove to dislodge)? Will that force on a stuck case cause bullet setback and a resulting overpressure round? The patent application is silent on these aspects of the design.

This patent was assigned to the U.S. Army, which would lead one to conclude that the three inventors worked for (or were enlisted in) the military.

It’s an interesting idea, and would probably be suited to use with caseless ammunition.

Now about the mystery: there is some murkiness regarding this story. The pictures on TFB apparently came from a Russian blogger named Max Popenker, but there’s no indication of where he got them. A Google search and a TinEye reverse image search turned up nothing.

There is also a question about the chambering of the gun. Wikipedia reports that the rifle was supposedly chambered for 5.56×45 NATO, which would be impossible given the description in the patent application. This is further confused by the label on Popenker’s pictures, which say “Caliber 5.56mm”.

I suspect this is a case of mistaken identity caused by a bad assumption. First, the name of the gun — the “Dual Cycle” — is similar to one developed by General Electric during that general time period which may have used 5.56×45 ammunition. From what I could find they are in no way related.

Second, American readers would no doubt look at the caption on Popenker’s pictures and conclude that 5.56mm must refer to the NATO round, because that’s the only round in American terminology which is so designated. In the rest of the world, however, the .22 caliber is called 5.56mm and requires a cartridge length dimension to deduce the actual round!

Since Popenker’s pictures don’t specify the cartridge, only the bore diameter, I suspect that the gun was in fact chambered for a rimless, straight walled .22 caliber round in order to make the extraction scheme work. This conjecture is supported by the very short cylinder in his picture of the disassembled gun.

-=[ Grant ]=-


About the Author:

Grant Cunningham is a renowned author and teacher in the fields of self defense, defensive shooting education and personal safety. He’s written several popular books on handguns and defensive shooting, including "The Book of the Revolver", "Shooter’s Guide To Handguns", "Defensive Revolver Fundamentals", "Defensive Pistol Fundamentals", and "Practice Strategies for Defensive Shooting" (Fall 2015.) Grant has also written articles on shooting, self defense, training and teaching for many magazines and shooting websites, including Concealed Carry Magazine, Gun Digest Magazine, the Association of Defensive Shooting Instructors ADSI) and the popular Personal Defense Network training website. He’s produced a DVD in the National Rifle Association’s Personal Firearm Defense series titled "Defensive Revolver Fundamentals" and teaches defensive shooting and personal safety courses all over the United States.
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