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Discussion Starter #1
As .357 Magnum revolvers go, the Trooper MK lll was hard to beat. Incredibly strong, superbly accurate, and smooth as silk; its completely new action design was also extremely durable and practically maintenance free. Its new hand and ratchet design was exceptionally inventive providing nearly bank vault lock up without all the complicated and delicate parts of its predecessors.
As is inevitable with any new design there were a few hiccups. A handful of breaking triggers and firing pins in the early production didn't really amount to much of a problem. Most owners were completely satisfied, and went about shooting the heck out these sturdy guns, and many of these fine revolvers are still going strong after a half century of use.
However, there is one aspect of the design that over time has proved (to me at least) to be a little problematic. Colt is the only revolver manufacturer that I know of (other than the early Dan Wessons) to have the cylinder collar bear the force of the firing sequence directly on the frame. As the massive MK lll cylinder hammers away at the frame at both ends at each firing, end shake will inevitably develop over time. Unfortunately there is no way to correct this other than an expensive trip to the Colt factory since there is nowhere to place a shim for correction.
Colt never looked back after the MK lll, and every new revolver design since has been set up this way including the New 2020 Python!
Colt's intention in assigning Karl Lewis to do design work on the MK lll was to reduce production costs, yet maintain a quality product. He succeeded admirably! I'm just wondering if this change to the crane assembly was part of that objective, or was there some other reason.
 

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My understanding has always been that Colt's objectives were basically twofold...build a revolver that could withstand unlimited use of .357 Magnum power and be less labor intensive for assembly and repair. That involved some non-traditional manufacturing methods for Colt and maybe the gun industry such as sintered metal technology...an early form of MIM manufacturing. It also utilized a transfer bar safety...an old Iver Johnson innovation...years before Ruger made a big deal of their "innovation".

I would guess the design of the cylinder collar was simply to comply with the design objectives.
 

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Bob
Thanks for a nice overview. Please elaborate on a cylinder collar.
vic
 
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Since the beginning of the swing out cylinder Colt double action in 1889 Colt used a flange on the crane to position the cylinder, which had the cylinder collar made as one piece with the cylinder.
In those days the cylinder spaced on the flange, and the flange spaced on the frame just below the barrel.

Starting in the 1950's?? Colt discontinued the crane flange and began spacing the cylinder collar directly on the frame.
This was used on all Colt double action revolver models from then on.
The cylinder collar was still machined as one piece with the cylinder.

In the earlier flanged crane models a washer could be put on the crane to correct end shake, but Colt apparently didn't use washers for factory repairs, they either replaced the crane, stretched the cylinder collar, or somehow worked on the flange.
After the deletion of the crane collar, washers were unable to be used so stretching the collar was the only way to repair end shake.

So, the non-flange crane system was used well before the Mark III series was developed.
 

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Discussion Starter #6
Thanks for clearing that up for me, dfariswheel. The early Pythons still had the crane flange system, so it had to be in the late 1950's that the change was made. Any way of tracking down exactly when this happened?
 

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Since the beginning of the swing out cylinder Colt double action in 1889 Colt used a flange on the crane to position the cylinder, which had the cylinder collar made as one piece with the cylinder.
In those days the cylinder spaced on the flange, and the flange spaced on the frame just below the barrel.

Starting in the 1950's?? Colt discontinued the crane flange and began spacing the cylinder collar directly on the frame.
This was used on all Colt double action revolver models from then on.
The cylinder collar was still machined as one piece with the cylinder...

So, the non-flange crane system was used well before the Mark III series was developed.
Many thanks!
Vic
 

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Discussion Starter #9
Just found a crane for a 1973 Python. Still has the crane flange. Are there different types of crane flanges?
 

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Since the beginning of the swing out cylinder Colt double action in 1889 Colt used a flange on the crane to position the cylinder, which had the cylinder collar made as one piece with the cylinder.
In those days the cylinder spaced on the flange, and the flange spaced on the frame just below the barrel.

Starting in the 1950's?? Colt discontinued the crane flange and began spacing the cylinder collar directly on the frame.
This was used on all Colt double action revolver models from then on.
The cylinder collar was still machined as one piece with the cylinder.

In the earlier flanged crane models a washer could be put on the crane to correct end shake, but Colt apparently didn't use washers for factory repairs, they either replaced the crane, stretched the cylinder collar, or somehow worked on the flange.
After the deletion of the crane collar, washers were unable to be used so stretching the collar was the only way to repair end shake.

So, the non-flange crane system was used well before the Mark III series was developed.
Hey DF! great to see you posting! I haven't visited this site in a long while and miss you informative posts on another site that we frequent. Hope all is well for you and yours!
On topic, I almost bought a nickel MKIII last year at a pawnshop. They wanted 2k for it. I wonder if I should have picke it up...
 

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Discussion Starter #11
From what I've been able to research it seems that 1966 was the year for the change over to a crane without a flange. The Diamondback was introduced that year, as were reissues of the Cobra, Agent and Detective Special, all with the new crane arrangement. The Python apparently held on to the crane flange at least up to 1973, but not sure when it was changed over.
 

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Discussion Starter #12
Karl R. Lewis began working at Colt on January 2, 1964 with the title of Advanced Development Engineer. From the announcement in the Colt newsletter; "Mr. Lewis is responsible for the research, developing and designing of firearms to meet Colt's long range marketing requirements". So, it is very likely that Lewis did design work on the Diamondback as well as the Cobra, Agent and Detective Special reissues. His "crane without a flange" was already in place before he began his extensive design work on the Trooper MK lll.
This is my theory anyway. To rebuke this, all we need is verification of a Colt revolver made before 1964 that has a crane with no flange, and I'm perfectly OK with that. I honestly would rather the "loss of the crane flange" be on someone else rather than Karl Lewis, as I personally don't think it was such a great idea.
 

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Discussion Starter #13
Anyhow, continuing on to other aspects of the MK lll. This revolver has been touted as one of the strongest mid-frame .357 Magnum revolvers ever made; designed to withstand unlimited use of full power Magnum loads. Also, in 1969 these were still "real" Magnum loads not like the watered down commercial loads of today. Yet these revolvers are quite often found to have excess end shake.
The cylinder of a MK lll is massive compared to a Dan Wesson for example. I think that extra mass may have been a contributing factor to the hammering effect, and the corresponding end shake development.
Also in question is the allowance of only .003 of end shake on these revolvers. Was this manufacturer tolerance, or end user tolerance? In other words, could there have been MK lll's going out the door with up to .003 already present, or were they all set to near zero at the factory?
Karl Lewis did a few things a little differently on his Dan Wesson design. First, the cylinder was lighter. Second, he designed a spring loaded detent ball to not only align the cylinder but to also absorb some of the shock when firing. Lastly, instead of the cylinder collar being made one piece with the cylinder, he made the collar a separate part that fit into a milled out pocket that could be removed and shimmed underneath should some end shake ever develop.
Don't get me wrong, I dearly love my MK lll, and even though it's relegated to just .38 Specials now it will always be one of my favorite guns to shoot.
 

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I’ve got the Dan Wesson and several MKIII’s. In several ways I definitely think the DW is superior, but there’s just something about my Trooper III that I love. Also, as you said I suspect a lot of the MKIII’s came from the factory with either more than .003 endshake or they were right at it because I don’t ever remember handling one that didn’t seem to have endshake.
 

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Discussion Starter #15
I recently read a review of the New King Cobra Target where the author's new revolver had .003 end shake out of the box, so even with our 21st century manufacturing technology they're doing no better than they did 50 years ago. Honestly, .003 isn't all that bad, and I've never had a problem with my MK lll.
 

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Discussion Starter #16
From what I've been able to research it seems that 1966 was the year for the change over to a crane without a flange. The Diamondback was introduced that year, as were reissues of the Cobra, Agent and Detective Special, all with the new crane arrangement. The Python apparently held on to the crane flange at least up to 1973, but not sure when it was changed over.
1974 was the year the Python was changed over. Some still have the flange, and some do not. So the Diamondback was the first Colt revolver design to not have the crane flange from the beginning of its production run. The Trooper MK lll was the second.
 

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Discussion Starter #17
Just read an interesting article on the Trooper MK lll in a Gun magazine from February 1970. One (stock) photo shows three of the gentlemen who designed the MK lll looking over the final drawings in an office at the Colt factory. The fourth, Karl Lewis, had apparently already moved on to a new adventure with Dan Wesson when the photo was taken.
The others were: Paul LaViolette (product engineering manager), Richard Baker (designer) and Henry Into (design project engineer). I'm guessing these four men may have also worked together to design the Diamondback a couple of years earlier.
No 'new' idea simultaneously develops in group thinking. Most likely one of these four men had to be the first to say something like "how would it be if we removed to crane flange altogether and let the cylinder collar ride directly on the frame?" After half a century, we may never know. I'm fairly certain Karl Lewis has passed on; no way of knowing about the other three.
 

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This rather depends on "Designed".

The Mark III was a totally new design not based on any older Colt revolver.
It required a development process after the original mechanical idea was designed.

The Diamondback was really just a dressed up Police Positive Special "D" frame.
That was just a matter of cosmetics in making it look like a miniature Python.
Not much was there that needed any actual design work by mechanical engineers.
 

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Discussion Starter #19
Unlike its D frame predecessors, the Diamondback does not have the crane flange. Just trying to pin down the when and why this occurred.
 
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