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Python Timing - pin missing primers, advice needed - UPDATE

3K views 18 replies 8 participants last post by  ponyup 
#1 · (Edited)
Hi all,
thanks for a great forum and resources found here!

I recently managed to find a 4" Python, after years of searching (they don't come along that often in Norway), I am probably the second or third owner of this gun, but it appears to have been cared for.

It works perfectly in SA, and regularly manages 1,5" groups on 25M (rested.....) with the right ammo.

The problems start with firing double action: In short, the hammer falls early on two consecutive chambers, but works perfectly on the other 4. The hammer seems to fall a fraction of an inch before lockup is acheived, with the pin hitting the primer about 1,2mm left of center, leading to two failures to fire. It is consistent, every time.....when the gun does lock up with the trigger back and the hammer dropped, it is tight as new. The serial # is T92xxx

I am hoping there is only the question of a small part (hand? Bolt?) that needs replacing..... but since I do not want a scope on it, nor a stock "bedding" job:rolleyes:, precious few gunsmiths in these parts would be trusted with the job, so I am hoping it's a DIY job.....

Sending it back to the factory for a tuneup from over here is a no-go, unfortunately, and finding a dealer who would do so, would be hard, and it would lead to a wait of possibly several months if not years....

Any advice? Has anyone had the same problem?

Thanks In advance!

KK

In know most people know how these look like, but posts needs pics.....

Firearm Gun Revolver Trigger Starting pistol
 
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#2 ·
The only advice is to figure out some way of getting that great python back to Colt. What U described is out of time, Colt or someone well versed in pythons will be able to fix it. Please dont let just any gunsmith work on it , if they dont know about pythons they will only make it worse or ruin it. Sorry about ur prob., but great looking snake. Cheer up it can be fixed
 
#3 · (Edited)
Thanks gruesome,
I believe I will have to take it apart to diagnose the trigger sear and the hammer spur, and perhaps the bolt (thank A1A also).

Could stretching the hand, or replacing it help?

It is frustrating to have nice python in less that 100% shape!

Anyone else come across this particular problem?
KK
 
#4 ·
Your first step should be to order a copy of the Jerry Kuhnhausen Shop Manual on the Colt revolvers, Volume One.
This was written as a training aid for gunsmithing students to teach the Colt actions as they are repaired by the Colt factory.
This contains everything you need to diagnose and repair your Python.
It's about the best money a Colt owner can spend, if nothing else just to know if their Colt is working properly.
Since the author trained students for the factories, all techniques shown are the techniques used by the factories:

THE COLT DOUBLE-ACTION REVOLVERS - A SHOP MANUAL | Brownells

(Brownell's will ship to you).
If you don't feel up to repairs yourself, you might loan the manual to a gunsmith so he can teach himself how the Colt factory does repairs.

With that said, your Python problem may be more serious.
Usually, a standard out of time Colt will be out of time on all chambers. A problem on only one or two suggests something more is wrong, possibly an excessively worn or damaged extractor, or a cylinder crane that's bent from being slammed open and shut, or dropped.

Such is the old Colt action design, unless the timing is just horribly off, the gun will lock up in double action when the trigger is pulled.
The hand system design assures full lock up in double action, so if your Python isn't fully locking in double action, especially on just two chambers, you have something more serious than just a worn hand.

Best advice: One, STOP SHOOTING THE GUN.
Off center primer hits mean the gun is firing with the cylinder unlocked and not aligned with the barrel. This is DANGEROUS. DON'T shoot it until it's repaired correctly.

Two, Buy the shop manual so you can properly diagnose exactly what's wrong.
STUDY the manual. It was written as a training AID for students and the instructor who wrote the book figured the student would have the sense to read closely. For that reason he didn't write important info in big letters with arrows pointing to it.

Three, when you order the shop manual, also order the following Brownell's gunsmith screwdriver bits and a "law enforcement" screwdriver handle.
These few bits will perfectly fit the Python screws and will prevent damaging them.
The law enforcement size handles are the perfect size for good control. Buy either a magnetic or clip-tip type, or both.

Bits. Buy the following. The reason for two bits in each size is to fit screw slots that may vary or be worn:

Magna-Tip Bits | Screwdrivers & Sets at Brownells

.150-2
.150-3
.180-2
.180-3
.210-2
.210-3

Handle. You can use your own, but these are the perfect size:

LAW ENFORCEMENT HANDLES | Brownells

Bottom line: When a Colt fails to lock up in double action something is very badly worn. When it is just failing to lock up on only one or two chambers, something is VERY seriously wrong and it will likely be more than just one thing. This can be difficult to diagnose, so the shop manual is a necessity, lacking a Colt qualified pistolsmith.

Read the manual, and understand the action fully before altering ANYTHING. Colt's are very non-intuitive and altering something without being absolutely certain that's the problem will only ruin parts that may be irreplaceable.
 
#5 ·
Thanks dfariswheel!
Great insight, and advice. I will follow your recommendations, and post my "findings".

The cylinder does lock up on these two chambers, but only after the hammer has dropped, and as the trigger is released.

I will of course as suggested, read the shop manual, and I am looking forward to learning more about htis.

Truly great to get advice like this, reflecting true insight!
Thanks again!!"

KK
 
#7 · (Edited)
daveall,
I wish I could do that....
For all who have followed this: Newsflash! My initial diagnosis was wrong! The problem is actually cylinder overtravel, and the bold misses the slot. Deepest apologies for the mistake!

This happens only with rapid DA firing (with snap caps this time). This is checked so far (after finding Kuhnhausens book in the self. Bought it to tinker on -77's and -78's, which seems simple by comparison.....):

1. I have checked the crane, and it seems fine, no gaps or anything else to remark.
2. No endplay over factory spec.
3. The ratchet fingers are not all exactly the same diameter across, but hard to measure exactly with my caliper.
4. The bolt engages the slots on SA and slow DA "firing". But only comes up about 0.073 from the frame.
5. On rapid firing the bolt engages the cylinder, and follows as it should but skips the slot on two consecutive chambers, even though it seems to have the spring tension needed.
6. While keeping the trigger depressed, I can press the cylinder back into lock, and feel the trigger moving forward.
7. The angle of the top of the bolt seems low/not steep enough, just looks that way, without having empirical proof yet......

This is as far as I have come for now. According to Kuhnhausen, the bolt needs to be checked, so once Brownells gets me the screwdrivers recommended above, its "hammer time".

I suspect the lack of a Colt gunsmith in this country is to blame for this, and some enterprising previous owner, hereafter called #¤%&/&/(@, has taken upon himself the "fine tuning" of this gun at some point.....

Thanks again for all input and advice, and keepem coming!

Heres a pic of how the firing pin hits the primer on fast DA.
Ammunition Metal Button

KK
 
#8 ·
Wow As dfaris said I definitely would not shoot it in da! Maybe this is a candidate for bending the bolt tail to get it to drop sooner in the grooves/leads before the cylinder notch. The bolt is probably dropping Very late.
I had a few that threw-by also. Tweeking the bolt tail did work for me on those with that problem.
 
#9 ·
As you probably know by now, this is known as "Cylinder throw-by". That's a condition where the cylinder rotates TOO far, and bypasses a cylinder notch.

Here's some areas to check.

Look for burrs or damage of the two cylinder locking notches it's bypassing.

Check the bolt head for excess wear or burrs.
If the bolt head is excessively worn, check for cylinder roll back. This is where you can rotate the cylinder backward when the action is un-cocked and at rest.
If you have an excessively worn bolt head, it may be possible to elevate the bolt. This is covered in the shop manual and requires filing the shank of the bolt near the head and lowering the rebound for proper pickup.

Check the action for old lubricant or impacted fouling.
Often you get sluggish bolt operation from a gummed up action, and a slow or sticky bolt can allow throw-by.
Also check the bolt spring to insure it hasn't been damaged, altered, replaced with a lighter spring, or is rusty or fouled.

Check the timing of the bolt to insure it's dropping in about the middle of the leade or "ramp" in front of the cylinder locking notches.
If it's dropping to close to the locking notch, it may cause throw-by. This is a timing issue.

Check your shooting technique. It's possible to induce throw-by by a hesitant or jerky trigger pull, or by trying to "stage" the trigger in double action.
 
#10 ·
Thanks again for staying with me gents. Really enjoying my path to becoming a Python smith!

The bolt does drop right at the beginning of the lead, on all modes of firing. I will go back and check for burrs, and once the screwdrivers are in, the bolt will get a better examination, including the spring and screw.

I am leaning towards a weak spring, shot bolt, or some such, as suggested above. I will also clean out the mechanism, as from what I have seen, grease has been applied in some places.
Stay tuned, and tbanks again!
Kk
 
#11 · (Edited)
All,
so heres the latest, after two "diagnosing and "repair" sessions (I use those terms loosely....):
I waited impatiently for Brownells screwdriver bits to arrive (I could probably get the same stuff here, but I do not need much on excuse to pick up a bunch of stuff at brownells,...).and followed the advise to not fire the revolver.

1. I read the Shopmanual by Kuhnhausen as advised. I have this in my library, and it should have been the first point of reference. Thanks for the reminder!!!!!!
2. Carefully opened the revolver.
3. Completely cleaned out the black grease and residue inside the action, and oiled lighlty & carefully.
4. Very carefully filed down a very small amount of metal off the part of the bolt, that impacts on the inside of the frame when it locks the cylinder, as the Bolt was a little low (0.073) compared to the recommended 0.08 or so recommended. (As advised in the book, I did not go all the way at once, which was good it would appear).
5. Carefully countoured the bolthead that interacts with the cylinder, as the cylinder drag mark was slightly off center, I though I would take a chance and "fix" it....
6. Checked the bolt spring and screw. Everything seemed "fine" ( I'm not a gunsmith remember.....:cool:)
7. Reassembled it all (take photos when doing this, have the Book next to you, and be thorough and patient.......unlike me :mad:).
8. I inserted some snap caps into the cylinder and dry fired. Vigourously. Eureka! It all worked as it should in dry firing mode, both SA and DA, even with the two stops that were regularly skipped by the bolt. Time for the range!

9. This is where it all fell apart......I had stocked up on the chepaest .357 ammo money could buy, and everything worked as it should (like it always did) in SA mode. Then came time for DA....Bang, bang, bang, bang, bang, CLICK, Cylinder skipped a beat (throw by) and the primer was missed! #¤%&/()=)=(/&. :bang_wall:
:mad:Back to the workshop...

1. Tried all chambers with dry firing/snap caps. To my surprise I now had 3 chambers that would be skipped with dry firing!!! I marked them all off.
2. Checked for burrs in the bolt stops. Nothing "unusual". If it had been, I would probably not have spotted it, or subconciously chosen to ignore it. I probably would have had to get a new cylinder, literally impossible here.....
3. Under a magnifying glass, I the returned to the bolt head interaction with the bolt stops. Remember I messed with this before. So under a magnifying glass I carefully checked again how it interacted with the stops. and found: a. It is not a timing problem, the bolt engages very early in the leade groove. b. The drag line in the leade groove is slighly to the rear of center (see pic),
Automotive exterior Bumper Auto part Vehicle

(note the white ink marking the correct cylinder stops) c. The edge of the bolt head does not seem to follow closely enough to the cylinder groove surface. I conclude that this may casue the bolt to jump the stop either because of the slighly higher elevation that it would have if dragging along a higher part of the rear edge of the leade groove, combined with the fact that the edge of the bolt that drop first into the bolt stop, did not track as close to the cylinder as it should. It would appear that the previous owner, Mr. "#¤%&/(=)(/&% had been there with a file as well, to "fine tune things a little". The bolt surface was in fact slighly oval, lifting the leading edge off a little.
4. Out comes Mr. Diamond file, and the bolt head is a. Contoured, and b. the angle is adjusted to follow the surface of the leade track more closely.
5. Reassemble.
6. Dry fire with snap caps. Upside down, lefthanded, slow fast, very fast, tilted to both sides.
7. Eureka!!!! ( I think)

The problems seem to have been narrowed down to the the bolt contour. I will have to live fire the gun to make sure it is all as it should, but this is where it stands now. It will probably take me about two weeks before I can get to the range again, but this isn't over yet!

Thanks again to all who have led me onto the right path. Even though it may have seemed apparent, this time it really got me out of the box, and into the book, to get things started the right way around!

Stay tuned for the range report!

KK
 
#15 ·
I don't know the availability of gunsmiths in your part of the world but to become a COLT qualified gunsmith where you are the only option would be to find a current gunsmith that has many successful years under his belt repairing COLTs and then intern with him for a number of years. The next and probably the biggest hurdle for you would be finding COLT parts. How many people in Jordan own a Colt firearm and how many would need them repaired? Probably not much of a market, if I were to hazard a guess.
 
#16 ·
Dear Sir I am able to come to the USA any time and to be trained by recommended people if you can help me ,colt pythons are around and were usually given to selected people as royal gifts by the late king Hussein of Jordan ,it a petty not to know how to keep the in good shape as the are very beautiful
 
#17 ·
There are no places that will train you ONLY on the Colt revolvers.
What's available are gunsmithing schools that teach you how to be a professional gunsmith.
Some of the better schools will add extra education on specific subjects like the Colt revolvers, but that's along with the entire program.
These professional schools take at least two years and cost a lot of money.

This is one major reason why there are few Colt qualified gunsmiths working in America today. There's no one to train them.
 
#18 ·
So.....
I thought I have fixed the problem, dry fired with dummies, etc etc, placed the gun in the safe and waited for range day...opened the safe, and as I would live fire the gun for the first time after following "the book" and all genereous advise here religiously, I dutifully tried it with dummies again:

Same problem! Still! so I decided to send it to the witch-doctor (cantacerous gunsmith, mentioned above): Colt smiths are non-existent here, and he could not help, so I am no longer the owner of a Python......my favourite revolver:bang_wall:

I am however, now the owner of a Detective Special :D ok, not the same gun, but still the one I regret not buying when it was on the shelves way back when! And before anyone asks: I did carefully and bvigourously dry-fire it with dummies before trading in the Python, and coughing up the cash.

Accuracy is "great" and no issues so far.

Again; thanks a million for all the great advise on the forum, and had I been handier with the file and hammer, I may have been able to rescue it. It was certainly worth a try, and I am glad I did.


KK
 
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