'72 Open-Top Timing Woe!!!???

[Crow Choker]

Hi All--Several years ago I purchased a '72 Open-Top Army Model from Cimarron (shoot 44 Colt blk ctgs and mild 44 Spec smkless). So far with the exception of stoning a small burr off the recoil shield that was tying up the works a little, I haven't 'touched the inards' as I like to shoot em a while for any 'quirks' to surface. I'm getting a line approx. 1/8" long on the cylinder before the start of the groove milled for the bolt stop. This isn't a light line you see on alot of revolvers, but it's as if the bolt is trying to mill a groove into the cylinder. The line follows the front portion of the grooves (all six-towards barrel) before the bolt locks into the bolt stop. I've read L. Pettifoggers info on tuning Pietta's and Uberti's, but saw nothing on this problem. From other readings and what I know about the single actions functioning there could be a number of reasons. Is the bolt leg that works off the hammer cam to short or out of adjustment? Does the cam on the hammer need work on it? Is it a comination of the two? Does the bolt itself need some work, ie stoning/reshaping? Maybe a new bolt? Other timing aspects are good, alignment of barrel and cylinder, trigger let-off, lock-up. I know its hard to determine when you don't have the gun in hand, but would appreciate some input/ideas from anyone having similar problem in the past. Would submitt picture, but haven't figured as of yet how to go about it. Thank you for any info. Yers, Crow Choker

[Raven]

Sounds like your bolt is droping early.
It should drop at the beginning of the lead.

If it is not droping too early you can pean the bolt leg to adjust the timing. Some people will tell you you can pean the cam as well but personaly I would avoid this.

A new bolt is cheap. I would fit a new bolt

Another thing that can cause the scoring is by letting the hammer down from half cock. It is a good idea to always pull the hammer to full cock before letting it down.
When you lower the hammer from half cock it lets the bolt up against the cylinder and then drags against it till it reaches the next bolt notch

Good luck
Raven

[Crow Choker]

Thnak ya Raven-The bolt dropin' too early is what I suspected too, but is this becasuse the leg on the bolt that comes off the cam is too short or just out of adjustment. Negative on the letting the hammer down while on half-cock.

[Raven]

Bolt leg being short is most likely. If it's had some use it's probably from wear.

Raven

[Pettifogger]

First thing to do is take it apart and clean and inspect everything.  Bolt legs are usually pretty hard steel and don't usually wear "shorter" unless you have fired a LOT of rounds.  Check the hammer cam to make sure it is not damaged or worn and make sure the hand spring and bolt/trigger spring are OK.  On most Ubertis the cam is cast as part of the hammer so it is not replaceable.  (It can be "replaced" but the cost will most likely be more than a new hammer.  Requires milling off the old cam, making a new cam, drilling a hole in the hammer and pressing in the new cam.)  Check the bolt legs to make sure one or both isn't bent inward.  As an experiment you can spread the legs on the bolt a little so they are making definite contact on the frame and the side of the hammer and seeing if the early drop goes away.  If the legs are bend-in or weak (or there's a bunch of dirt in there) they will drop off the cam early.

[Fox Creek Kid]

Pettifogger is right about the cam. I have two old '72 OT's and the cams were really worn. LOTS of BP rounds. One has over 10,000. I sent one to a top 'smith who ''gutted'' it and also drilled out the cam and put one of his own making in it. He even welded up the gas collar & machined it back to eliminate end shake. It now cycles like a Ferrari piston.  As Pettifogger stated, it is cheaper to buy a new hammer, but mine are real case colored & nickel respectively & I wanted to use the same hammers.

In essence, as with any gun repair, the solution is usually time = MONEY. 

[Crow Choker]

Thanks for the response LP and FCK. As previiously stated, I haven't done anything to the action, haven't even 'tore' the gun down since getting it in July of 08. Can't be from wear, less than 1000 rds threw her. Will have to take apart next week-end and see what I find. Might be some 'crud' in the works. Will advise.

[Pettifogger]

Cap fragments???   Are you talking about a cartridge gun or C&B?

[Raven]

72 Open Top has gotta be a cartridge gun 

Take it apart! if the cam is bad order a new hammer. If the bolt is bad stetch it first and then order a bolt. Nothing on an Italian gun is very Hard! and have seen plenty of bolts worn. And without that many rounds through them! Every time it is dry fired counts the same as firing it.

Raven

[Crow Choker]

OH OH!!!!! Sent off that last reply without proof reading properly.  The right side of my brain musta been thinking cart gun and the left cap and ball. Went back and redid the cap fragment business. Too busy this weekend to tear into the gun, will try next week-end. It tis a '72 open-top cartridge gun I've been talking about.  

[Montana Slim]

Yup, bolt leg length or cam for sure. I've never had luck pounding on a bolt leg myself, but it could be woth a try

I like the simplicity of replacing a cam vs. fitting a new bolt, so I've setup some of my revolvers with replaceable cams. This way i use a relatively soft cam, which wears out (rather than wearing the bolt)...then I simply install a new cam when the timing starts to misbehave.

Probably not for everyone, but maybe someone can use this tip.

Regards,
Slim

[Raven]

To pean the bolt leg put a small bar of steel between the two legs and then with that set up on a bench block pean the leg.
Works very well!

Raven

[Fox Creek Kid]

...so I've setup some of my revolvers with replaceable cams...

M.S., how'd you do this? Did you make a jig to hold the hammer while you drill out the Italian integral cams?  

[Montana Slim]

M.S., how'd you do this? Did you make a jig to hold the hammer while you drill out the Italian integral cams?  

Nothing special...Just used an adjustable vice (I can clamp on the flat, then rotate in multiple axis to get it perp to the drill) that mounts to my drill press. First, I ground the old cam flat...almost flush....then, center-punched (by eye) the best guess of center (the human eye is fairly accurate)...then drilled away. Forgot the drill size I used...I have a small stash of cams I bought years ago for $1 each. A guy who wants the cam to last a bit longer could easily harden them. I've considered having a fixture made to produce my own cams. Maybe someday when I'm retired and need a lil project. I'd guess I replace the cam after 2-3 years of use. Like this on my Pietta Armys since I already have the trigger and rear sight (hammer "V" adjusted just where I want-em).

Another trick of the replaceable cams is that you can rotate them a tad one way or the other, which tweaks the timing.

The steel in the hammer isn't very hard...could probably make a decent job using a corded 3/8" hand drill.

Slim

[Asa Smith]

I resently purchased 2 new 72 open tops imported by Stoger/Uberti.
One had the firing pin bent up so far it was hitting the frame when lowered.
The second gun had the timing issue you are refering to.
I sent both back to Uberti, they bent the firing pin on the first down and called it good, the second they said worked to specs.
The gunsmith did call me when working on the timing issue, I understood he was going to attempt to repair, I receved the gun back with a new bolt in the box for me to install.
I installed the bolt and it fit without any work but the gun still had the timing issue, same as before, I tore it down again and found the cam was rounded at the front edge and was causing the bolt to drop to soon.
I called Uberti and ask, if they were unwilling to repair the gun, would they send me the parts, they agreed to send the firing pin on the first gun but required I send the gun back to have the hammer installed on the second gun.
I'm still waiting for them to send a pick up as I paid shipping the first trip, I figure they should pay this time.
We will see how this works out.
All this to say, I would guess your problem is due to a missmanufactured hammer cam.
My gun is in the X107xx serial number range, could be they had a few made wong at the same time.
Hope this helps
Asa Smith
PS I own 9 of these guns (conversions and open tops) and this is the only one with the timing issue.

[rifle]

Crow Choker, the replies you have from the gang is all good. You have to see the gun for youself since no one here can actually see  it to determine the actual problem.
You may have the problem mentioned about the misplaced at the factory cam of the hammer. Like a good cam and  a new bolt can have the new bolt leg too short. 
That being the case the new non-integral cam installed(as long as it's larger in diamerter than the factory cam) can fix it up so the bolt legs of new bolts will be too long and keep the bolt on the cam too long. That means you file the bolt leg a little at a time to get the timing right. The timing "right" to me is when the full width of the bolt hits the cylinder with it's leading edge even with the leading edge of the bolt notch. You can time it so the bolt hangs over the notch edge as much as half it's width but if the trigger/bolt swpring is on the stiff side the bot can begin to peen down the leaqding edge some. That's why I like to time so the full width of the bolts head hits the ramp/lead in. That can minimize the bolt head peening down the notches leading edge.
I think on some of these Open Tops with the distance between the cam and end of the bolts leg being what it is getting the full width of the bolts head hitting even with the cylinder notches leading edge is the best it'll get with stock parts. A new cam would remedy that and give more margin for timing the way you would like it.
I like to soften the hammer before drilling a new hole for a replacaceble cam. Some hammers are hard and too difficult to drill a hole in the slanted face of the old cam. I like to punch mark the center of the cam so it's position isn't lost and then drill a pilot hole with a small drill and then drill the hole full size for a snug fit of the new cams post in the hole. Once the hole is drill I mill the old cam off flush. "Flush" being important so a milling machine is good to have. After the new cam(already in a hardened state) is in I reharden the whole hammer firing pin and all.
Anywhooo......if a new cam is needed you can determine that by looking at the cam and bolt leg comparing the bolt leg to a new bolt to see if it's worn off any and a new bolt can fix the problem and seeing if the cam is worn or defective by eye-ballin it.
It's hard to understand the exact problem of the gun as you describe it. I see iy may be a case of the bolt head needing conformed to the center of the lead-in or ramp so it doesn't dig into thye side of the ramp where the bolt hits in there off center. You have to see if the bot leg hits before the contours of the ramp which means a timing problem or if the bolt is deforming metal by not hitting the cylinder early but by hitting the cylinders ramps off center.
If it's merely hitting off center you have to remove metal from the bolts head till it's contour is riding on the center of the ramp and sitting in the notch with it's highest point in the center of the notch and riding the center of the ramp/lead-in.
I'd fix it fer ya free of charge except for shipping and the cost of the new bolt or cam or whatever and ,maybe, a little donation to the "Funds for the Poor" charity where I am the "POOR"  but I don't have the FFL stuff so......I'd send it to one of the FFL'ers here like Raven and get it fixed up A-OK. I'd go with a new hardened cam over a whole new hammer since the problem could still be there even after a new hammer is installed.

[crs555]

Hi all, I'm brand new to SASS and this forum and I just bought a pair of 1860 Army Conversions and I'm having the exact same problem with one of mine. (the other one had it's own set of problems but that's a whole different story). My timing is so advanced that second position happens simultaneously with the first click. which prevents the gun from being placed in half-cock. and has resulted in a lovely nOOb ring on the cylinder.

I'm fortunate to have two of them so I can take parts out and diagnose, but it seems to be both the hammer cam and bolt. I took the bolt from the good gun but it seems the frame wasn't milled deep enough so the correct bolt won't fit, and I put the hammer from the bad gun in the good one and mostly fixed the problem but the timing was still causing it to drag for 1/8th of an inch. The bolt from the bad gun fits in the good one since it was milled deeper, but again timing was advanced (though that could be due to the difference in frame dimensions and the bad bolt having to be machined down to fit.

I'd like to get a new bolt and see if I can correct it with that, but other than getting one from the factory is there a manufacturer that makes replacement parts? I've heard talk of wolf springs but I didn't know if they, or anyone else makes parts for these guns.

Also what are you all using for stock to replace the old cams after you've drilled out the holes? Seems the back of an old drill bit would do the trick, but as with the Dillon locator button in Pettifoggers articles there seems to be a random part to fix anything.

Sorry if I've asked questions that have already been answered or questions that are just plain stupid. I'm just trying to get these guns working so I can get out and practice a little before my first match.

[rifle]

It's almost easier fxing the guns than typing about fixing them. I read my reply above and saw where I typed "bolt" when  I meant to type "cam.That made what I typed seem ridiculous.
One problem I see with the RM types from Uberti is the half cock notch cut too deep and too close to the cam. That makes the bolt leg let off the cam too soon. There can be burrs there too making the bolt leg let off early. Weakening the bollt side of the trigger/bolt spring can help that some.
A new installed cam that's thicker works well in this situation. You can buy new cams that are hardened. Drill a center hole with a small bit.....mill off the old cam.......drill the right size hole to press fit the new cam......turn it to where the most is gotten from the new cam in the way of timing and all .......adjust the stock bolt leg....go to shootin again with good timing.
Having more thickness to the new cam is the trick.
In my opinion the cams and the way the half cock notch is cut too close to them is a design defect or a quality control problem where the inspector lets the hammers pass by with half cock notches cut too deep and too close to the cams. The bolts leg has a little trouble riding over that open space where the half cock notch is. The small area that should be there close to the cam for the bolt leg to ride on is cut away. I've welded the end of the bolt leg to be longer after diamond filing away some of the cam the make the little shelf next to the cam for the bolt leg to ride on.
I've eased the bolt legs tension between the hammer and frame also to keep the bolt leg from getting into the half cock notch and cutting away a groove in the cam.
I like to install new cams that are thicker and hold the bolt leg longer and correct the timing.
The real culprit is the overly deep half cock notch though and welding it a little less deep and filing the weld smooth and cleaning up the half cock notch is what gets to the cause .......and not treating a symptom.
Anywhoooo........new thicker cams can solve the problem the easiest way.
Hope this helps out in some way. Ifin you were in the neighborhood you could drop by and I'd show how to fix er up or help you fix er. I have a coupla Buddies that take advantage of my good nature that way all the time. ha ha ha ha Always helpin them fix their guns. Mostly cap&ballers though.