How the Chiappa Rhino works, part IV: single action lockwork.

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One of the things that struck me when I first opened the Rhino is that the trigger doesn’t directly do anything. In every other double action revolver the trigger directly contacts the hammer in both single and double action, but not the Rhino!

In a traditional revolver’s single action the sear (which is usually a pointed projection on the trigger) drops into some sort of notch on the hammer. When the trigger is pulled, the sear slips out of the hammer notch, allowing the hammer to be propelled by the mainspring and fire the cartridge. This system has persisted with only minor change for over a century. It’s a simple, robust method that’s easy to make and easy to maintain.

It’s not nearly so simple on the Rhino.

Take a good look at the pictures, because this gets very complicated very quickly!

The Rhino is cocked, as we learned last time, by pulling back the external hammer, which pushes the cocking lever down, which pushes the hammer spring lever down against the tension of the mainspring. The hammer spring lever draws the hammer back.

At this point, the long extension on the front (right) side of the hammer slips past the spring-loaded single action lever (aka ‘sear’); the single action lever springs back (counter-clockwise), trapping the hammer in the cocked position.

When the trigger is pulled, it pushes on the connecting rod which is connected to the interlink lever. (These are all official Chiappa part names!) The interlink lever and the single action lever share a common pivot point, and are separated by a phosphor bronze washer (not seen in these pics.) As the interlink lever rotates clockwise, a small pin on it contacts the downward-pointing extension on the single action lever, pushing the extension and causing the sear surface to rotate upwards and slip off the hammer extension. The hammer is now free to rotate clockwise, propelled by the mainspring through the hammer spring lever, which brings the top of the hammer into contact with the frame-mounted firing pin.

Got that?

It’s an extremely complicated way to approach the function, though those familiar with high-end rifle triggers, which typically use a series of levers to do the same task, will recognize what the Rhino is doing. Those more familiar with handguns will be left staring at the pictures, scratching their heads, and saying “what the ****?” (It very much reminds me of the operation of a Hermle chiming clock, a mechanism with which I am intimately familiar. I’ll leave it to you to decide if that is good or bad.)

In the next installment we’ll have a peek at how double action works. It’s a little more conventional, but still unique.

-=[ 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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