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Page Handguns » Colt
Posted: 2/26/2007 1:43:04 PM EST
I have an Old Colt Detective special that the the timing is off on. I won't be able to get much for it selling it, so I figured rather than send it to Colt and spend more than it's worth I could try to fix it myself. I took it all apart, and none of the parts seem all that worn, but I don't have anything to compare them too. Are there any parts that are normally responsible for this? It didn't have much for grease in it, should I use regular Breakfree, or put a couple dabs of axle grease in it. Is there anything in particular I should look for damage wise? Any other advise?
Link Posted: 2/26/2007 4:44:38 PM EST
[Last Edit: 2/26/2007 4:46:46 PM EST by CarrierKey]
I am a revolver armorer. Do you know what to look for? For one, the lifter (called a "Hand" on a S&W and a "Pawl") on a Ruger. Your cylinder may not be indexing your Cylinder properly. The "Lifter" is HEIGHT SENSITIVE, NOT WIDTH SENSITIVE and carries up your Cylinder. Can be that your gun is not lifting to top dead center. There are other things to look for like the Bolt width, but you need someone that can understand and properly grasp the Colt system. Last Armorer school for wheel guns at Colt was like 1971. CARRIERKEY
Link Posted: 2/26/2007 5:22:28 PM EST
I was a Colt DA revolver gunsmith for 30 years.

My best advice is to send the gun in to either Colt, or Pittsburgh Handgun Headquarters.

Second best advice is to buy a copy of Jerry Kuhnhausen's book, "The Colt Double Action Revolvers: A Shop Manual, Volume One":
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=13805&title=Jerry+Kuhnhausen+SHOP+MANUALS

This is a real pistolsmith's training book, and it explains the Colt old type action and how it works.
Fair warning: the old Colt action really is somewhat of a watchmaker's design, and the working surfaces are TINY, the action is NOT intuitive, and each and every part does at least TWO separate functions, usually not related to each other.

Likely your timing issue is where the hammer cocks, but the cylinder isn't locked.
This can be a fairly easy fix, but read the book before trying it, it isn't fixed the way you'd think.

As an aid, here's how to check Colt timing:

Here's how to check the timing on the old style Colt revolvers.
This covers all old style Colt DA revolvers including:
The 1917 and New Service. Official Police, Officer's Models, Detective Special, Police Positive and Special, Old Model Trooper, Diamondback, and Python.

To check Colt timing:

BOLT RETRACTION AND "SNAP BACK".
Open the cylinder and look at the small "lug" in the bottom of the cylinder window. This is the cylinder locking bolt.

Cock the hammer, and watch as the bolt retracts into the frame and pops back out.

The bolt MUST begin to retract THE INSTANT the hammer begins to move.
There MUST be NO (ZERO) hammer movement possible before the bolt starts to retract.

The bolt should retract smoothly with no hesitation until it's fully retracted, then it MUST pop back out with a clean "snap".
There should be no hesitation, and no amount of "creeping" back out.

CYLINDER UNLOCKING.
Close the cylinder.
Use your left thumb or fore finger to again cock the hammer, closely watching the cylinder bolt as you SLOWLY cock the hammer.

As the hammer comes back, the bolt will retract away from the cylinder.

The bolt MUST retract far enough to unlock the cylinder BEFORE the cylinder begins to rotate.

If the bolt is still slightly engaged with the cylinder lock notch, the cylinder will be attempting to turn while still partially locked.

This produces a "catch" or "hard spot" in the trigger pull and will damage both the bolt and the cylinder lock notches.
This often appears as metal "pulled out" of the lock notches, with rounded off and burred notches.

BOLT DROP TIMING.
Continue to cock the hammer, laying your right index finger on the cylinder just enough to prevent "free wheeling".

Watch for the bolt to drop back onto the cylinder. WHERE the bolt drops is CRITICAL.

The bolt MUST drop onto the lead or ramp in front of the actual cylinder notch.
If the bolt drops too soon, (in front of the notch ramp), it will mar the finish of the cylinder.

The bolt SHOULD drop into about the MIDDLE section of the ramp.

If the bolt drops late, (farther toward the actual locking notch) the revolver may display "cylinder throw-by".
In this condition, during double action shooting the cylinder may rotate PAST the locking notch, and fire in an unlocked condition.

It's the nature of the Colt action, that a hesitant or jerky trigger pull by the user can induce throw-by in even a properly tuned Colt.
The Colt trigger should be pulled with a smooth, even pull, with no sudden jerks at the beginning.

CYLINDER LOCKUP.
Continue to pull the hammer back and both watch and listen for the bolt to drop into the cylinder lock notch.

The bolt MUST drop into the actual lock notch BEFORE the hammer reaches full cock.

The most common Colt mis-time situation is the hammer cocks before the bolt drops into the lock notch. (Hammer is cocked, but cylinder isn't locked).

In this condition, with the hammer fully cocked, you can push the cylinder slightly, and you will hear the "CLICK" as the bolt drops into lock.

In my experience, most Colt's leave the factory with the bolt dropping a little late into the lead, but usually wear in to correct timing.

If the bolt drops onto the cylinder early, no real problem, but there will be extra finish wear.

If the bolt drops late (closer to the lock notch) the cylinder may "throw by" or rotate TOO far in double action and this can cause off-center primer hits and firing while unlocked.

Each of these checks should be done on EACH chamber. All of these checks are better done individually. In other words, do the bolt retraction check on all six chambers, then do the bolt drop test, and so on.

A properly tuned Colt will:
Have a smoothly functioning bolt with no sticky or hesitant movement.

Unlock before the cylinder begins to turn.

The bolt will drop onto the middle 1/3rd of the ramp.

The bolt will drop into the lock notch before the hammer reaches full cock.

Have a smooth trigger pull, which does "stack".
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