. . timing issue . .

[Wolfgang]

Hi pards . . . I'm a '58 Remington shooter . . . but have a Colt problem right now.

On my bench is a Pietta '51 Colt clone belonging to a friend of mine.  It locks up and will not cock sometimes.  The bolt is not dropping quite soon enough and occasionally ( not every time ) catches on the cylinder while the hand is turning the cylinder.  How do I make the bolt drop just a tad bit sooner ?   

Thanks in advance for assistance . . . . 

Probably won't be back on the forum until monday the 28th.

Good shootin' . . whether Colts or Ramingtons . . . . 

[Shotgun Franklin]

Did you check the bolt spring? It's the one weak link in a Colt. I've found a cracked spring, even a very tiny crack to cause timing problems.

[Abilene]

Where'd all the gunsmith's go?  Well, on a used gun I would suggest the bolt may be worn at the point where its leg contacts the cam to start the bolt dropping.  Thus requiring a new bolt.  I've seen some new Ubertis that had this problem, fixed by dressing down the head of the bolt a bit as it was protruding through its window in the frame more than needed.  Keep the shape and angles the same, just slightly lower.  So it gets out of the way of the cylinder notch sooner, but still fully engages the notch at full cock.  Don't know if that would work on your buddy's gun or not.

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[Professor Marvel]

        1)On my bench is a Pietta '51 Colt clone belonging to a friend of mine. 
 ->    2)It locks up and will not cock sometimes. 
        3)The bolt is not dropping quite soon enough and occasionally ( not every time ) catches on the cylinder while the hand is turning the cylinder. 

 How do I make the bolt drop just a tad bit sooner ?   

Greetings My Dear Wolfgang -

As Monsiuer Franklin mentioned, start with the spring!

Our good Abilene is spot on regarding "how to adjust  the bolt "

However - item 2 just jumps right out at me - if the bolt is engaging the cylinder notch but you cannot completely cock the hammer, that suggests that  the hand may be too long. Normally the hammer is prevented from coming to full cock by the hand
still pushing against the ratchet teeth. - by shortening the hand, the bolt will drop sooner in the cylinder turn, and ensures the
hammer can come to full cock.

yhs
prof marvel

[Wolfgang]

Thank you for the replies.   I realize that I was not quite clear in my description of the problem.  When attempting to cock the hammer it only moves to the rear about 1/4 inch and then the gun locks up as the bolt has not dropped quite enouth to completely clear the notch in the cylinder.  So the question is . . .

. . . . . . what to I do to make the bolt drop just a tiny bit sooner ? 


 I'll have a look at the bolt spring later this evening.

[Doc Sunrise]

Wolfgang,
I believe you are saying the bolt is rising to engage the cylinder too early.  This is happening because the camming legs of the bolt has slipped by the hammer cam, which allows the bolt spring to force the bolt to push up into the frame window to engage the cylinder stop too early to allow the cylinder to rotate properly, which will then block the hand from moving anymore and stop the hammer from being pulled back anymore.  I would say a couple of things need checked.  The camming legs of the bolt, and the hammer cam.  Many guns have been found to have these areas not tempered properly, or very soft metal, or layers of metal peeling off, which causes thin metal areas, or improper camming angles, or even broken bolt legs.  Atleast that what it sounds like to me.

[Wolfgang]

Marvel & Sunrise,... thank you for the responses, . . .

Marvel . . I'd considered shortening the hand so that it begins to turn the cylinder a little later and gives the bolt time to drop down and clear the cylinder notch.  Not having tinkered previously with such things I was holding off doing anything until I had advise from those more experienced with such goings on. 

Sunrise, .... the problem is that the cylinder has just begun to be turned by the hand and is stopped from turning futher by the bolt still catching in the cylinder notch.

ps.. Incidently the gun is brand new.  I'd given it to the friend several years ago for Christmas but he had never had a chance to shoot it until recently and we discovered the problem. 

Thanks again for the replies.   

[Doc Sunrise]

It still sounds like the problem is in the bolt leg and hammer cam area, or the bolt spring.  Do not shorten the hand.  When the hammer is returned by shooting or by hand, the hammer cam which is angled slips by the top of the bolt leg that is angled as well, and then the hammer cam snaps in under the bolt leg.  The bolt spring is needed to push the bolt leg down against the hammer cam, and the bolt leg needs to be angled in width properly to be in contact with the hammer cam, so the hammer cam can slide down the bolt leg and re-engage itself on the bottom of the bolt leg.  When the hammer is pulled back, being already engaged with the the bolt leg, it forces the bolt to pivot down against the bolt spring.  If a bolt leg angle and hammer cam angle is not correct, or if the bolt legs are not spread wide enough, or the bolt spring is broken or not angled correctly, or if the thickest part of the hammer cam has broken of or slivered off, the bolt is not going to drop properly or at all.

I have also seen where the bolt trigger spring was not installed properly to where the trigger has disengaged the spring and allowed it to go past the trigger face.  This could allow the spring to become jammed and not allow the bolt to push against the spring and move it. 
 

[Wolfgang]

Doc Sunrise,... thank you for more information.   I had resisted any thoughts of shortening the hand for fear that it would then not turn the cylinder far enough to come into battery.   The trigger / bolt spring seems fine.  I have the trigger guard / lower grip fame peice off of the pistol.  That the bolt comes up to high was a possitility I'd considered and taking down it's profile as suggested by Abiline seems like one possible "fix".  I'm busy this evening and most of the day tomorrow ( must make a journey into "town" from the isolated area where I'm located ) . . . will get at it on the bench again tomorrow afternoon. 

Thanks again for replies.   

ps.  I have another Pietta '51 Colt replica on hand that is mine and which I've never shot.  I may dig that one out.  See how it functions and thus have a functioning one for comparison. 

[Mako]

Wolfgang,
One of the things you can do to better understand the timing of that particular revolver is simply remove the cylinder.  This allows you to watch the bolt drop and the rise without any interaction from the hand and the cylinder.  Watch your bolt carefully as you cock it about twenty times.  Make three marks on the side of the hammer with a pencil to determine where the bolt is is doing these three things:

• Beginning to move at the same point in the hammer arc.
• Dropping lower than the cylinder notch at the same point in the hammer arc. You need to mark the bolt where it protrudes from the frame  for this one.  You may have to take the cylinder in and out several times to get this mark right.
• The Bolt is released by the cam on the side of the hammer at the same point in the arc in 20 cockings.  

You need the engagement of the bolt to be as deep as practical.  You do not have a two stage hand that helps keep the cylinder locked up during firing ans therfore a short bolt leads to other issues.  The "tail" of the bolt where it engages the cam, or the cam are always first suspect when the timing is off.   I was trained that shortening the bolt protrusion was your last resort and usually not the source of the problem.  It is just a way of dealing with a symptom.

As Doc Sunrise already said there could be a problem with the cam or the bolt leg.  sometimes a burr on the cam keeps the leg from engaging as it should.  The bolt should begin to move almost immediately as you cock the hammer.  If it doesn't, then it is a bolt leg or cam problem.  It has to move before the first step of the hand engages the ratchet.  The trick to fitting a leg to the cam is allowing just enough clearance between the cam and the radius on the leg to allow the leg to always snap into position, but provide no additional clearance than other what is needed to assure the leg always travels back up the bevel and snaps over the cam when the hammer is dropped.  This has to work whether the hammer is dropped or the hammer is gently lowered.

When I see a leg with excessive clearance it is usually because someone has monkeyed with the bolt protrusion and the bolt was lowering and unlocking the cylinder before the hand had engaged the cylinder.  Sometimes the cylinder rotates a bit and can even "back up" You can feel the "hitch" and to "correct it" someone starts messing with the bolt/cam timing.
  Let us know what you find.

Regards,
Mako

[Pettifogger]

As you have gleaned, the problem with timing issues and trying to diagnose them on the wire is that we are talking a few thousands of an inch on a few key surfaces.  The ONLY way to find out what is wrong is to take the gun apart and look.

[Wolfgang]

Mako & Pettifogger, . . . thank you for the replies.   Tomorrow I'll have time to dig out of "deep storage" my two Piettas Colts  ( a '51 that never was,....  ie. .44 cal.  and a '60 Army )  It will be interesting to see how they operate.  I put them both away when I bought them and haven't touched them since.  Presuming they function properly I'll have a working mechanism for comperison and can then tackle pulliing the "inerds" out of my friend's '51.  It is another "gun that never was .44 cal.)

I'll post again tomorrow evening. 

Thanks again , ..... 

[Wolfgang]

Update on this problem … progress ? . . . . Gremlins ? . . . .

I dug out my other two pistols that are the same gun.  .ie.  All are Pietta made.  My friends is a brass framed  .44 cal. ‘51 Colt clone (ie.  A “gun that never was”.)  Mine are a steel framed .44 cal. ‘51 Colt, and a steel framed ‘60 Army ( which is identical except for the barrel assembly.)   Mine have never been fired.  Both had been turned once when I bought them and then put away.  My friends has been fired 6 rounds.  (  We fired out the 6 loaded chambers by loosening the barrel assembly and getting the cylinder to turn when it would jam so as to give him a chance to actually shoot it after his having it for 5 years unfired, . . .  and to get the chambers unloaded before working on it.) 

 Anyhooooo…. My pistols function perfectly.  His cylinder put into either of my pistols function perfectly. 

 I tried both of the other cylinders in his pistol. 

Both would jam and fail to turn on only one chamber and always on the same one chamber!   

Whut is going ON ? !   

Gremlins ? ? ? …. I could then loosen the barrel assembly, wiggle the cylinder to get it un-stuck, and proceed to cock 5 times just fine,….. and then they would jam again on the same chamber.  It was the same with both of those brand new cylinders.   I’m more than confused.   

Anyhow …. On tear down.  The screw for the trigger / bolt spring is frozen and soaking overnight with penetrating oil.   

[Mako]

Wolfgang,
You need to describe the jam in more detail.  For instance, does the hammer move back at all?  Is the hammer all of the way forward on the chamber before the "one that jams?"  I have seen tall tubes, or tubes that haven't been screwed in that don't allow the hammer to go far enough forward which prevents the tail of the bolt from snapping over and engaging the cam.

For grins try this quickly.  Remove the tube on the chamber the hammer sits on when it won't cock and see if it will now cock.  This type of lock up is the worst jam you can have while firing.  Sometimes it is caused by a piece of cap that gets in the hammer channel and gets smashed by the falling hammer.  It prevents the hammer from going far enough forward to allow the bolt leg to engage the cam and you are locked up.  You can't cock and you're dead in the water.

What you are describing may simply be loosening the barrel which allows the hammer to move forward as the cylinder moves forward.  This allows the leg on the bolt to snap over the cam.  I wish the smashed cap fragment was as easy to relieve.

Regards,
Mako

[Wolfgang]

Mako . . . "tubes" . . ?  are your refering to the nipples ?  I presume.   It isn't caps jamming as the gun is not actually being fired.  The hammer moves back about 1/4 inch or maybe even less and then the jam occurs. I'll have to measure that in the morning when I'm in the shop again.  I had not considered a tall nipple that didn't alow the hammer to be all the way forward.  That sounds like a possibility.   I'll have look at that possiblity tomorrow also.  

Thanks for the reply.  

Moving the cylinder forward ( by loosening the barrel ) does releive the jam.  

[Mako]

Mako . . . "tubes" . . ?  are your refering to the nipples ?  I presume.   It isn't caps jamming as the gun is not actually being fired.  The hammer moves back about 1/4 inch or maybe even less and then the jam occurs. I'll have to measure that in the morning when I'm in the shop again.  I had not considered a tall nipple that didn't alow the hammer to be all the way forward.  That sounds like a possibility.   I'll have look at that possiblity tomorrow also.  

Thanks for the reply.  

Moving the cylinder forward ( by loosening the barrel ) does releive the jam.  

Wolfgang,
I know it wasn't a cap jam. I was just describing how a perfectly timed percussion revolver can have the same failure because of a cap fragment preventing the hammer from moving fully forward.  Remember a perfectly timed Colt's pattern revolver barely allows the bolt leg to snap over the cam, this requires the hammer to be fully forward.

Loosening the barrel makes it sound suspiciously like a failure of the bolt leg to snap over the cam.  The hammer moving back that short distance fits this scenario, by the way that's exactly what happens with a cap fragment jam I described. The ability to clear it by loosening the barrel definitely fits.

This is the failure mechanism if the bolt leg doesn't reset:

• The bolt does not reset so it never moves as the hammer is cocked.
• The Cylinder remains locked.
• The hammer can move back until the hand is blocked by the ratchet.

The hammer moving about 1/4" is how much clearance you have until the hand engages the ratchet.  It is during this distance the bolt has to be fully withdrawn from the notch in the cylinder.

If it is a high tube, don't start changing it until we determine the correct way to change it.  If you change the cone or the seating face you will change the cap fit.

Regards,
Mako

[Wolfgang]

Mako . . . OK !  The problem is now understood. 
 
If I remove the cap from the nipple that is up when the jam occurs the pistol will no longer jam as the hammer is able to go far enough forward for the bolt leg to snap over the cam.  This is true on the two cylinders from my pistols when used in my friend’s pistol.   All three cylinders will function perfectly in my two pistols with caps on all nipples.  So. . . The internals in my friend’s pistol will not tolerate the slight difference in the forward movement of the hammer that occurs with the caps on the very slightly higher nipples, while the internals in both of mine tolerate this slight difference in the forward movement of the hammer.  This explains why he’d had no experience with the pistol jamming until we got it to my range and put caps on it prior to shooting it.   

But . . . The next question, . . . What do I do to fix the problem ? 

[Mako]

Wolfgang.
Good, it seems we are making progress.  I'm going to show you two illustrations.  The first is a general one to show how the cylinder/cone relationship is set by the bearing surface on the frame.


The second is going to show you four dimensions we can use to find out what is going on with the cone face of the tube threaded into the cylinder.



I'm going to tell you up front it is the "C" dimension that I am always concerned about.  If this varies too much from chamber to chamber it is difficult to get the cone heights all the same and usually requires a "spot face" of this surface with an end mill to get everything on track.

The one dimension I didn't show we'll call "E", that would be the difference between "C" and "D".  It is the distance from the bearing surface on the rear of the cylinder to the cone face.  This is the magic dimension that is causing your problem.  Now we just have to find out what the offending feature or part its.

If you have access to a caliper and a tube wrench do the following (be sure to record all of your measurements to three places) :

• With the cylinder out of the frame mark all chambers 1 through 6
• Measure and record all "A" dimensions.
• Measure the "B" Dimension.
• The difference between the "A" and "B" dimensions is also another way to report the "E" dimension.
• Measure one of your good cylinders the same way and compare the "E" dimensions.

If you have a tube wrench, remove each tube from the "bad" cylinder (keep them in the correct order by chamber).

• Measure the "D" dimension on each tube from the flange face to the top of the cone.
• If you have used a caliper as a depth gage before of if someone is handy that can help you, measure each  "C" dimension for each chamber.
• Measure a couple of "C" dimensions from one of your "good" cylinders.
• Measure the "D" dimension on the tubes from those chambers.

After you get those, report them back here.

Regards,
Mako

[Wolfgang]

Mako . . . . Thanks for the very detailed images of the cylinder and nipples.   I do have dial calipers for making measurements.   However, . . . . It seems to me the better “fix” for the problem would be to adjust the internal relationship between the arm of the bolt and the cam so that “click over” occurred sooner.  Now that I know what I’m dealing with and what to listen for I can hear the click of the bolt over the cam on my two pistols when the hammer is still quite a ways from the capped nipple.  On the problem pistol the “click over” occurs just before the hammer would touch the capped nipple and on the nipple that is too high if I let the hammer touch it and very gently press the hammer against the cap I can hear the click”.  And then there is no jam. 

I’m keeping in mind that this is not a fine high quality pistol.  It is a cheap brass framed Italian made “clone” of a Colt.  ( It was only $ 130 back when gave it to him for a Xmas present 6 years ago.)    I can see an “easy fix” by just removing the nipple that is high (or maybe replacing it with a nipple off of another cylinder that doesn’t create a jam.)   And giving him that cylinder with the pistol.  The actual cylinder that came with the pistol originally is at his place in Palm Springs.  He’d charged the chambers and so I left it and have used my cylinders for experimentation rather than bother with pulling the balls and charges. 

He is not doing Cowboy Competition shooting,. . . . his use of the pistol will be very limited.   He’ll come out here to the ranch once or twice a year.  Will shoot out the 5 or 6 rounds on the target range.  Then shoot his Colt 1911 that is his “ real use pistol”, clean them and put them away for another 6 months. 

On the other hand .. . . In view of increasing my gunsmith skills it would be interesting to take apart the inner workings and to modify them so that the bolt “clicked over the cam” sooner and to alleviate the problem that way.   Is that a practical approach ?

At any rate . . . Let me have the benefit of your greater expertise in such matters . . .

Nothing to do with it today or tomorrow anyhow . . It is windy as all hell here in southern California and we have a bus load of French tourists at midday both today and tomorrow who get a lunch and then a show about movie making and tour of the movie set.   I’ve been busy cleaning out the stove in the saloon, so as to get it going,  and trying to get set up for the show with things tied down so that they do not blow away. 

Much thanks again for your very informative replies. 

[Mako]

Wolfgang,
That may be the course of action, but I have a question for you...How much are you planning on taking off?  

Don't get the cart before the horse.  There is actually method to my request for dimensions.

Knowing which chambers work and those that don't work as well as the associated dimensions will help us know how much to remove and where.  It may be as simple as a burr, it may require removing material in an area I can show you.  If you want to increase your gunsmithing skills the best course is by observation and diagnosis.  Modification is the "solution" we all want to jump to, but it is not the best way to learn, or even solve the problem.  I've seen very experienced and skilled gunsmiths jump to the "solution" and later realizing they had not correctly observed.  No two problems are ever the same, they may be very similar, but never the same.

Regards,
Mako