By now everyone knows about the Rhino’s unique hexagonal cylinder, but it’s unusual in more ways than the shape. The extractor (star or ratchet, depending on the maker) on the Rhino is quite different in execution than any S&W, Colt, Ruger, Dan Wesson, or Taurus.
The orthodox method of making an extractor is to cut half circles to accept the cartridges, and mill cam surfaces in the center so that the hand can rotate the cylinder. The extractor does double duty, as it were.
Those cam surfaces are responsible for both rotating the cylinder and locking it in a precise position when the gun fires. The extractor must stay in perfect relation to each chamber if barrel-chamber alignment is to be maintained. If the extractor rotates even slightly relative to the cylinder, the chambers won’t come to the exact position for every shot, and in severe cases an out-of-time condition can be caused.
The common method of maintaining that alignment was to insert a couple of steel pins (very small pins!) into the web between opposite chambers, and drill the extractor arms to fit over those holes. That requires precise machining and fitting, two things which have become cost prohibitive.
In recent years S&W has approached the problem by simply machining the outline of the extractor, and the cylinder recess into which it fits, into something resembling a square. This is not an entirely satisfactory approach, as there is significant play between the two pieces. Ironically, that’s what the machining is supposed to prevent!
Because of this sloppy fit, modern Smiths must be timed with fired casings in the chambers, which immobilizes the extractor. The downside is that if live ammo is undersized, the extractor is free to rotate and the problems come back.
Chiappa decided on a very expensive method to obtain barrel/chamber alignment. They took the alignment pin idea, and instead of using them to fix the extractor they inserted four more, and use those as cams to rotate the cylinder! The extractor is drilled to simply fit over the pins, and serves only to push empties out of the gun.
(This concept of separation of function will show up later when I detail how the double- and single-action sears work.)
Chiappa’s method has the advantage of taking all extractor movement out of the equation. The disadvantages include a) they are not easily adjusted if chamber/barrel alignment is off, and b) the system is very expensive to produce.
The first disadvantage is evident in the gun I’m reviewing: two of the chambers are ever-so-slightly off, and a correction will not be easy. Keep in mind that the amount of discrepancy is very small, and doesn’t apparently affect the accuracy of the gun to a great degree, but the error does exist. The first gun, which I sent back because of a very heavy trigger, did not have the error.
The second disadvantage doesn’t seem to concern them, as we saw in the previous article on their breechface insert. Again, the machining is quite well done, despite the slight error noted.
If properly done, this design would make for very precise and repeatable chamber indexing, but if extreme care isn’t taken in execution that pursuit of perfection can result in a permanent deficiency. This is not unlike Colt versus S&W cylinder locking: the more precise Colt requires more care in manufacture and maintenance, while the sloppier S&W mechanism makes for a more tolerant system. Both have advantages and disadvantages that the gun designer balances to get the desired performance characteristics.
In the next installment we’ll dive into the internals, starting with the hammer that isn’t a hammer – and you might be amazed at what it takes to render the gun double action only.
-=[ Grant ]=-