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Old June 23, 2013, 02:48 PM   #1
dahermit
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Colt .38 Police Positive

Have an old Colt P.P. in .38 Special that I bought a couple of months ago for the main purpose of studying the action.

After studying the action, I have concluded that it is not very friendly to gun tinkerers. Comparing it to the S&W's, the action seems to be more complicated than the Smith & Wesson's that I am accustomed to working on. A smith seems to have parts that are more separate units, whereas the Colt seems to have just about every function inter-related.

Also, the Colt does not seem to offer as much opportunity for improvement as the S&W does... save for putting a bend in the mainspring.

Admittedly, I have not acquired the Kuhnhausen book on the double-action Colt. But, at this point, S&W's seem a whole lot more user friendly.

An aside: The gun was shooting about 6 inches to the left when I got it and discovered the front sight was a few degrees short of vertical. The gunsmith removed the barrel and took a few thousands off and set the barrel back one turn. However, now I cannot see any light between the end of the barrel and the cylinder. I can fit a .002 feeler in there but I think that the gap is a little too tight. Does anyone know what the specs are for the gap?

Any comments welcome.
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Old June 23, 2013, 03:44 PM   #2
Dixie Gunsmithing
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As long as the cylinder turns freely, to me, the less gap the better.

The major difference between the Colt and S&W is the rebound mechanism, but both do what they're meant to do. Even though it may not look like it, the S&W still has to go through similar operations to work. The Colt is a good gun, just different than a S&W.

Also, you can still stone a Colt, the same as a Smith, to improve trigger pull, etc. They're both well built revolvers.
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Old June 23, 2013, 06:07 PM   #3
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Ideally the gap on a revolver, including the Colt's is right around 0.005".
The range should be about 0.004" to 0.008".

Today's S&W says that a gap of under 0.012" is in spec. In the old days they held to the 0.004" to 0.008" standard but have loosened it up quite a bit.

If your Colt is a .38 Special, the guns actual model name is the Colt Police Positive Special.
The Police Positive was the same gun only made with a shorter frame and cylinder for use with the old short cartridges like the .32 and .38S&W.

As for the Colt's complexity, you're exactly right.
The old Colt action is extremely complicated and the critical working surfaces are tiny, to the extent many people don't even realize they are a critical working surface.
Almost all action parts were hand fitted at the factory by a master fitter stoning and bending parts to get it assembled and adjusted to operate correctly.
In the Colt, every part performs at least two totally separate functions, neither of which is related to the other.
Make a small change "here" and something totally unexpected happens over "there".
The old Colt action is somewhat rightly known as a "watchmakers gun".

This is why so few of todays gunsmiths either know how to work on the old Colt action, or are willing to take one in.
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Old June 23, 2013, 09:55 PM   #4
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Part of the story is that over the years since c. 1899 (the first S&W M&P) or 1909 (the advent of the "new" Colt action), the S&W lockwork has undergone a continuing series of product improvements, not all of which are reflected in the "change" numbers. Very few of these were even noticeable on the outside and S&W liked it that way. Anyone with a Model 1899 can take a look at such parts as the trigger rebound and the cylinder stop, to see what I mean.

Colt, once they had a reasonably successful system, "froze" it and ceased even trying to improve the internal design, though they made cosmetic improvements for marketing purposes (e.g., ramp sights, ejector rod shrouds). Then when Colt did decide to change, under economic pressure, they no longer had the capital to ride out the inevitable resistance to change and work out the "bugs."

Jim
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Old June 24, 2013, 06:30 AM   #5
dahermit
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Quote:
Also, you can still stone a Colt, the same as a Smith, to improve trigger pull, etc. They're both well built revolvers.
But, unlike the S&W, I cannot swap-out/test the rebound slide spring with a series of lighter springs, or do the same with various weights of mainsprings. As I posted, the only spring option seems to be to put the well-known bend in the mainspring which seems to effect the trigger return spring as well. Nor, is there any rebound slide tunnel that can be polished to enable the rebound spring to glide during its function. I suppose I could clip two coils off the cylinder locking bolt, but it hardly seems to be worth the effort. If the workings of my Colt are the same/very similar to the more recent Pythons, then I do not think that I really want a Python (or Diamondback) after all. It would seem that the Colt will never have the very light, butter-smooth double actions that I have gotten on my Smiths.
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Old June 24, 2013, 06:37 AM   #6
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Quote:
In the Colt, every part performs at least two totally separate functions, neither of which is related to the other.
Make a small change "here" and something totally unexpected happens over "there".
The old Colt action is somewhat rightly known as a "watchmakers gun".

This is why so few of todays gunsmiths either know how to work on the old Colt action, or are willing to take one in.
On little error and the gun owner is S. Out of Luck...no replacement parts as in S&W. Thankfully, my PPS still functions, albeit with a very heavy double-action trigger pull.
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Old June 24, 2013, 08:24 AM   #7
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Recently, I purchased a Pocket Positive in .32 SW Long (.32 Colt New Police). After a range trip, we noticed a hitch in the double-action pull. Being a complete newby with the Colt double action lockwork, I figured "how hard can it be?" and dove right in. I studied the action thoroughly, watched a couple of YouTube videos, and began disassembling the revolver, looking for the glitch.

I found the glitch, about 50 years of no one cleaning the revolver. I also got an opportunity to look at 1920s era gun manufacturing, and there were lots of interesting things to see. Delicate machine work that we'll never see the likes of again. It was like opening a time capsule. I didn't try to stone or file anything, simply clean and oil the innards of that revolver. After two hours, I was done, the revolver was re-assembled, and I have a new appreciation for the way a Colt revolver was assembled during the 1920s. The double-action pull is slick as snot and the little revolver seems to shoot just fine.

That doesn't mean that I want to "get under the hood" again on that little gun. My 60 year old eyes ain't like they were even 10 years ago.
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Old June 24, 2013, 12:41 PM   #8
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.

Yep, you found the combination - Clean/oil them, and then just shoot/enjoy them for what they are.



.
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Old June 24, 2013, 09:13 PM   #9
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Replacement parts may be had from ColtParts.com (not related to Colt Firearms) or from Jack First. However, trying to find someone to fit those parts is another story. I had enough trouble with the bolt and hand. I haven't even tried fitting a rebound lever yet.
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Old June 25, 2013, 07:47 AM   #10
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Quote:
...The major difference between the Colt and S&W is the rebound mechanism,...
And the mainspring, and the hand, and the firing pin block, and the...
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Old June 25, 2013, 07:50 AM   #11
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The double-action pull is slick as snot and the little revolver seems to shoot just fine.
On mine, I cannot say that it is not smooth, but is so heavy it is not much fun to shoot double-action.
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Old June 25, 2013, 12:20 PM   #12
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If you want to see how this action works, you might take a look at an e-book by Gerard Henrotin titled, "Colt New Service Revolver Explained". He takes you step by step through the action, or the rebound system, the hammer safety, and the sear (hammer and trigger). Once you learn this, you can see what needs to be done to tune one of these. I admit that you have to hand fit some parts, but really, I never found it that hard on these, even building cam surfaces back up to get them to operate properly. Take your time, and it can be done, but learn the action first.

http://www.hlebooks.com/ebook/coNSload.htm
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Old June 25, 2013, 12:38 PM   #13
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I recently "fixed" a Colt OP by placing a coil auxiliary spring behind the rear of the bolt to keep the bolt engaged with the rebound lever. The bolt spring (part of the bolt) was weak and kept slipping off the lever cam. IMHO, the bolt is the trickiest part. The spring part is thin and can break or weaken over time, and the part can't be welded because the spring will be made useless. And it is the hardest part to obtain because so many were replaced that spare parts are very scarce. Maybe someone is making repros; if so, I am pretty sure they would require a lot of fitting.

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Old June 25, 2013, 04:23 PM   #14
Dixie Gunsmithing
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Jim,

There's two approaches to putting a spot of weld on the cylinder bolt end, and the first is placing a heatsink close to it, so it blocks much of the heat from traveling into the thin section just behind the cam lump. I've done this with two copper blocks in a vise, and put a quick spot of weld on it, without losing the temper.


The other way, is to put a spot of weld on it, then harden it again by quenching, then polish the spring area bright, and temper it to a blue color, to get the temper back to where it should be. It should be drawn blue from the edge of the screw hole all the way out. The latch end can be brought to a brown, just a little harder.
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Old June 25, 2013, 06:25 PM   #15
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Jack First Gun Parts is making "replica" Colt parts, mostly for the medium E&I frame models.

The Jack First cylinder locking bolt is very oversized and requires extensive shaping before it's even close to being able to be actually fitted to a gun.
However, when there ARE no factory new parts you do what you have to do.
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Old June 25, 2013, 07:29 PM   #16
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Hi, Dixie Gunsmithing,

I would have annealed and re-tempered that bolt had it been thicker, but it looked like someone had thinned it down and I was reluctant to try to re-work it. The timing was OK except that the bolt kept slipping sideways off the rebound lever cam even though the cam looked good. So I cut two coils off a coil spring and inserted them behind the end of the bolt. So far, it has held up fine and the gentleman is happy. I didn't guarantee it would hold and if it doesn't, I will try to get a new bolt.

Jim
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Old June 25, 2013, 11:35 PM   #17
Dixie Gunsmithing
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Jim,

Shame that was that way, and I wonder why someone would have cut it down that thin? Well they're not that thick anyhow, but maybe they thought it would cut down on trigger pull as the rebound lever is raised while cocking? If they ground this, they may have gotten it hot while doing so, and took the temper out of the thin spring portion.

If the spring you added was to try to come loose from behind it later on, you can always solder it to the back of it, just clean and flux it good, as lead/tin solder flows well below the temperature that would hurt anything. Something this small could be soldered with a common soldering iron. As long as it works, and keeps the lock cam pushed over onto the cam surface on the rebound lever, it will work.

I forgot to add, that the bottom of the cylinder bolt cam, and the top of the mating cam on the rebound lever, should be pretty flat, with no angle that would cause a sideways motion of the rear of the cylinder bolt. It should stay on top shelf until the rebound lever gets high enough, that the cyl. bolt cam falls off the front edge, similar to a sear engagement. With a weak spring tension, any angle other that 90 degrees, toward the outside, could cause the cyl. bolt end to move to the side and drop off.

Last edited by Dixie Gunsmithing; June 26, 2013 at 12:00 AM.
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Old June 26, 2013, 05:19 AM   #18
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The used tired Official Police I worked on.

The problem I had with the replacement bolt (used) is that the tail didn't slip back onto the rebound lever shelf and no trigger return. I worked on the bolt tail and then a little on the rebound lever shelf. I also bent the rebound lever to and removed any burrs on its finger. The sides of the hand were polished to remove any burrs. These measures did work and the bolt did reset into the rebound lever shelf.

However, the trigger return was partial and sluggish when the action was released or worked slowly. The spring was bent to provide more tension. The safety was polished as was the cramming surface between the hammer and rebound lever. It turns out that the hammer was hanging up on the safety so part of the safety was filed off. That worked.

However, the timing was off so when I tried stretching the hand (it had been stretched before), it broke. Thus I made a new one and fitted it.
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Old June 26, 2013, 02:28 PM   #19
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Hi, Dixie,

Your description of how things should work is OK, but we both know that on those Colts there is often a difference between how things should work and how they do work. That basic action is a combination of several European designs, but AFAIK the cylinder bolt functioning off the rebound lever that way is strictly Colt and apparently derived from that of the SAA and the percussion revolvers. Still, it was a lot better than the design of the New Army/Navy, its predecessor.

If you want to see an interesting way of locking the cylinder, check out the Model 1878 or the Model 1889 Navy.

Jim
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Old June 26, 2013, 06:09 PM   #20
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I suspect the famed cartoonist Rube Goldberg got his inspiration from the early double action Colt's like the 1878 and 1889.
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Old June 26, 2013, 09:49 PM   #21
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I should not have left dangling anyone who really is interested (OK, no one!).

Neither of those guns has notches in the cylinder; the hand does double duty to both turn the cylinder and lock it in place, using the ratchet. Since there are no cylinder notches, the flutes were carried well to the rear ("long flutes").

One interesting sidelight is that after the Model 1878 was discontinued, Colt used up left over Model 1878 cylinders on the SAA by cutting cylinder notches. These are the scarce "long flute" Single Actions, made c. 1915.

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Old June 27, 2013, 04:23 PM   #22
dahermit
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A thank you for you guys that have posted about the Colt mechanism. I appreciate your experience and my education.
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Old June 27, 2013, 10:13 PM   #23
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Barring Dfariswheel hanging out his single and announcing he will work on the older Colts, it behooves us to learn how they function, are disassembled and reassembled. I am currently working on an old Colt Police Positive 38 S&W. The manuals are out there-Kuhnhausen's, e.g.- the tools are there, all we need is the patience and the willingness to learn. I like to quote the words of the late Professor Richard Mitchell, aka The Underground Grammarian. In an essay in which he held that the US education system had some responsibility for Three Mile Island and the failure of the Iran Hostages Rescue Raid, he noted that a helicopter is a very complicated thing, an nuclear reactor even more so-but they are both finite things-"the human mind CAN know them completely."
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Old June 28, 2013, 07:27 AM   #24
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Barring Dfariswheel hanging out his single and announcing he will work on the older Colts, it behooves us to learn how they function, are disassembled and reassembled. I am currently working on an old Colt Police Positive 38 S&W. The manuals are out there-Kuhnhausen's, e.g.- the tools are there, all we need is the patience and the willingness to learn. I like to quote the words of the late Professor Richard Mitchell, aka The Underground Grammarian. In an essay in which he held that the US education system had some responsibility for Three Mile Island and the failure of the Iran Hostages Rescue Raid, he noted that a helicopter is a very complicated thing, an nuclear reactor even more so-but they are both finite things-"the human mind CAN know them completely."
That is a good perspective to have from the viewpoint of a person who wants to learn about Colts. However, from the perspective a person who wants a robust, trouble free, easy to fix, easy to modify, easy to tune, handgun, then they would be better off opting for a S&W.

As in my experience with a VW Beetle, the mechanics thought they were great because they could put the engine on a bench to work on them. However, from an owner's point of view, the reverse gear would wear to a bevel and could not be held in gear, the heat exchangers would rust-out, the front end was very difficult to keep in alignment, etc.

From an owner of a Colt view, I would rather they did not go wrong in the first place and if they do, I would rather that it would be easy to find parts, and a competent gunsmith that could fix them. As each day passes, there are fewer of both.

I think I understand why the double-action Colts were dropped by Colt...it was about time, and it was the logical thing to do due to its lock-work. At some point, when beating a dead horse, one will almost always come to the realization that the horse is dead. I think Colt came to that conclusion.
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Last edited by dahermit; June 28, 2013 at 07:37 AM.
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Old June 28, 2013, 07:29 AM   #25
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SIGSHR,

I quite agree. I got into horology, and I always hear folks say that its complicated as a clock or a watch, when clockworks are really not that complicated, you just have to understand them.

On these old Colts, you need to understand cam surfaces a bit, and linkages, but once you learn them, you can almost spot the cause of a problem as soon as you start looking at it.

I posted a link to an e-book earlier, from a Belgium author, and it is one of the best I have seen on these type Colt's.
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