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Old September 6, 2010, 02:08 PM   #1
LFRAME
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Colt Army Special SA Lockup

Hello, new to forum (forums in general too). I have a Colt Army Special that will not fully lock when the hammer is drawn back and the SA sear is fully seated. From this point, the cylinder will lock with just a slight push of a few degrees clockwise. The DA lockup is perfect and since I am new to Colts, I'm confused as to whether this actually may be the correct function of Colt in SA mode. The Kaun??? Manual does not state whether this is right or wrong. When the hammer drops in SA mode, the cylinder DOES rotate that final few degrees and locks. Using snap caps in both SA and DA produces strike marks identical. I've had this weapon apart multiple times and have studied it's workings pretty hard and can not see any reason other than a worn SA surface on the trigger causing this to happen. If it does indeed need to fully lock in SA, I can't see how "stretching" the hand would not cause binding in DA. ???
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Old September 6, 2010, 05:56 PM   #2
Webleymkv
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An Army Special would have the "old" Colt action and what you describe sounds normal. Try this test, cock the hammer and pull the trigger while holding the hammer back with your offhand thumb. The cylinder should turn a bit and lock into place. Gently lower the hammer while holding the trigger back. While still holding the trigger back, use your other hand to check for front to back and rotational play in the cylinder as there should be none. Granted, I'm working off of memory here from the 1953-vintage Cobra I used to have. If I've misremembered anything, I'm sure one of the Colt experts will be along with the correct info shortly.
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Old September 6, 2010, 06:12 PM   #3
LFRAME
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Thanks webley

It's soooooo simple when you see it. The trigger needs that little extra space to clear. When pulled, the hammer starts it's fall and the cylinder indexes just in time. The gun is tight as "bank vault" despite being a detroit police veteran. Some minor wear but nothing otherwise to worry about. Got a nice detail strip out and cleaning in the process!! The safety assembly was pretty much glued to the frame from the old dried up grease. Shoot be a great shooter for years. Thanks again...!!
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Old September 6, 2010, 06:48 PM   #4
Dfariswheel
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If you can very slowly cock the hammer and the cylinder fails to lock up, the gun is out of time.
Such is the old Colt design that as long as the problem isn't too extreme the gun will go ahead and lock when the trigger is pulled.
However, this IS a defect and the gun needs to be repaired.

As a service, here's my instructions on how to check the old style Colt revolvers for proper 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.

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, 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.

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 at least slightly 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 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 before the hammer reaches full cock.

Have a smooth trigger pull, which does "stack" or get heavier as the trigger is pulled.
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Old September 7, 2010, 09:34 AM   #5
Webleymkv
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Originally posted by Dfariswheel
Quote:
If you can very slowly cock the hammer and the cylinder fails to lock up, the gun is out of time.
Such is the old Colt design that as long as the problem isn't too extreme the gun will go ahead and lock when the trigger is pulled.
However, this IS a defect and the gun needs to be repaired.
Are you sure? What you've posted sounds right for a S&W, Ruger, Taurus, or even a newer Colt like a King Cobra, but they all have significantly different lockwork, particularly the design of the hand, than an older Colt like an Army Special, Police Positive, Official Police, or Python. Jim Keenan offered a good explanation of this in the revolver checkout thread.

Originally posted by Jim Keenan
Quote:
Not a problem. Due to the design, almost all the older style Colt DAs do not fully lock if the hammer is cocked slowly or the cylinder is held back. The reason is that the Colt double pawl hand cannot force the cylinder into full lockup and still have room for trigger motion to fire the gun.
This sounds right as the double pawl hand never leaves contact with the ratchet from the time it begins to rotate the cylinder until the time the trigger is released. This is the reason for the Colt "Bank Vault" lockup as the cylinder is held in place by both the locking bolt and the lower notch on the hand. Other designs like a S&W or Ruger can rotate the cylinder to lockup prior to reaching full cock because, so long as the revolver is properly timed, the hand is no longer in contact with the ratchet by the time the hammer reaches full cock in SA or by the time the hammer is released in DA.
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Old September 7, 2010, 06:21 PM   #6
Dfariswheel
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No, the old Colt action should lock the cylinder at or just before the hammer reaches full cock.

The reason the old Colt action develops the "hammer cocked, cylinder isn't locked" out of time condition is wear on the hand.
In order to correct this, the hand can often be stretched to lengthen it.
In a S&W or Ruger, you need a wider hand.

I always made sure repaired Colt's locked up properly with the cylinder locking bolt dropping into the cylinder locking notch BEFORE the hammer reached full cock.
If an old Colt does not lock up before or right with the hammer reaching full cock the gun is out of time and defective.
True, you can't have the cylinder locking too soon before the hammer reaches full cock, but there's enough room to insure it does lock and still have some hammer movement left to correct for future wear on the hand.

The reason the gun can lock the cylinder, then lock the hammer and still be able to fire, is because of "back lash" built into the action. When fully cocked the hand actually "over centers" and drops back down a tiny bit. Just enough so that in a properly adjusted action, you can time the bolt and hammer for cylinder lock up before full hammer cock.
On my personal Pythons, the cylinder locks and the hammer still moves at least 1/16" before reaching full cock.

For more full details on how the Colt cylinder locks at or before hammer cock, see the Jerry Kuhnhausen shop manual, which goes into full details and how to adjust the action to insure proper cylinder locking.
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Old September 7, 2010, 09:06 PM   #7
James K
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Well, I sold those "old" Colts when they were new Colts, and very few locked up until the trigger was pulled, and that was from the factory. Further, the Colt reps stated that the condition was normal and that as long as the primer strike was centered there was no problem. In other words, just as Webley says, the cylinder clicked into position as the hammer fell (and it always did unless someone deliberately held the cylinder back).

Jim
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Old September 8, 2010, 07:07 PM   #8
Dfariswheel
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That wasn't my experience.
Of all the new Colt's I saw, the cylinder either locked up at or before hammer cock or it went back to the factory for repair. When they came back, they locked up correctly.

I never had a Colt rep, engineer, executive, production line assembly fitter, or gunsmith tell me that a gun that failed to lock up properly was "normal".

Your experiences may vary.
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Old September 10, 2010, 11:42 PM   #9
salvadore
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All my Colts lock up before the trigger is pulled. I had a dick spec. that wouldn't lock up and took a punch to the second little thingy on the hand to idsplace enough metal...Maybe not, maybe I used the punch on the main hand below the second little thingy. anyway, it worked. I bought a OP from the early thirties that locked up timely, but with just a small amount of presure could be turned back out of the cylinder notch. pulled it apart and dressed down the bolt where it contacted the frame and solved that problem. I don't think working on old Colts is rocket surgery, but if it goes south it's hard to find parts.
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Old September 10, 2010, 11:43 PM   #10
salvadore
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oh my dog, i'm dyslexic
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Old September 11, 2010, 11:06 AM   #11
James K
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We have been here before, several times. The perfectionist says, "it must work the way I want it to work or it needs fixed." The more practical person says, "as long as it works the way it needs to, perfection is not required."

In practice, as long as there is no misalignment when the bullet moves into the barrel, it is of little concern whether the cylinder was properly locked up when the hammer was cocked, especially in an artificial test where the cylinder is held back by force to keep it from turning.

In my own experience, confirmed by a look at Kuhnhausen, a number of factors are involved in cylinder lockup, to the point that, in production, it would be hard to get all of them to work perfectly together. I would assume that if a revolver were sent back, a skilled fitter would make it work "right" by careful selective fitting, having on hand a dozen hammers, hands, and so forth, plus a set of files if needed. But that was not done with production guns, no matter what Colt's "party line" may have said.

Jim
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