New hand...Maybe, maybe not.
The Colt hand "can" be stretched ONE TIME to correct timing.
If the hand has already been stretched, almost always a second attempt will crack or shatter the part from work hardening.
To stretch you need the correct tool and you need to do it in the correct place, NOT where you might think.
The best advice is to invest in the Jerry Kuhnhausen Colt Double Action Revolver Shop Manual, Volume One.
This shows the process in deep detail and will make more sense........
By Jerry Kuhnhausen. Explains and simplifies the relationship between the cylinder, bolt, rebound lever and hand on the Colt D, E and I frame revolvers...
The correct test for timing.........
Load EMPTY cases in the chambers to prevent ejector looseness from giving a false test.
Put a finger on the cylinder just lightly to prevent freewheeling and SLOWLY cock the hammer.
The cylinder locking bolt should fully lock the cylinder just before or as the hammer reaches full cock.
If the hammer cocks and the bolt is not fully engaged in the cylinder locking notch, it's out of time.
People will tell you that they came from the factory not fully locking and that's normal...It ISN'T.
Get a 1/2 inch wide chisel and grind the end flat. Stone off the sharp edges and polish the end.
Use a steel bench block on a FIRM surface. You don't want any bouncing or moving or the part may break.
Make sure the block is smooth.
Put the hand on the block and position the chisel in the slot on the back side. DO NOT try to stretch the hand outside that slot.
Give the chisel a firm rap or two with a small hammer to stretch it, KEEPING THE CHISEL CAREFULLY AT 90 DEGREES.
Don't allow it to tilt in any direction.
After a couple of moderate strikes, assemble the gun and test progress.
This is a slow process because you have to fully assemble the gun each time, and striking too hard can crack or break the hand, not hard enough and the hand will work harden and break.
Once it's correct, polish the slot in the hand to remove any heavy impact marks but DON'T remove any metal.
If the hand has be replaced, buy a new replica from Jack First Gun Parts. These are basically as you'd get a new replacement from Colt and require full fitting and adjusting.
I strongly recommend buying the Kuhnhausen Shop Manual to avoid having to buy several hands and ruining them in blind attempts to fit and adjust them.
The manual goes into deep detail on fitting a factory new hand, including where to stone to fit and how to BEND the bolt for correct function.
Out of stock right now, but they actually make these themselves.......
original used Some parts may need additional fitting to accommodate wear in old firearms. Sorry, we are unable to do any international sales of firearms parts due to excessive cost and regulations.
Best advice.... Buy the manual, it'll save you a lot of grief and money in the long run.
If you have concerns about doing this yourself, or you find other problems, the best source of professional repairs for the older Colt's is Master Pistolsmith Frank Glenn in Arizona.
He's an American Handgunner magazine Top 100 Pistolsmith and offers full Colt repairs to factory standards and specs.
He offers very quick turnaround, and excellent pricing.
He's the go-to for the members of the Colt forum........
Frank Glenn-Glenn Custom Complete Gunsmithing Service Glendale AZ
Here's my directions on how to test the old Colt action revolvers for full timing............
CHECKING OLD MODEL COLT TIMING
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.
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, LIGHTLY 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 leade 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 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.
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 or just as 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 leade, 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 of the ramp.
The bolt will drop into the lock notch just before or as the hammer reaches full cock.
Have a smooth trigger pull, which does "stack" or get heavier as the trigger is pulled.