Timing Issue

[paleryder]

I went to the range the other day and I was trying to pay attention to the functioning of my two 1851 Navy replica revolvers. I was with my boy so I probably missed a lot but I did have a couple of occasions where one of the revolvers didn't turn the cylinder fully, at least when my son shot. This resulted in no fire. I adjusted the cylinder, cocked it and it fired fine. So, I looked at it when I got home.

At home, I checked both revolvers. The Pietta seemed to be timed correctly. No obvious markes on the cylinder. I hear three clicks: half-cock, what I think is the bolt being dropped/released, full cock. I am assuming that the bolt is locking in at full cock because I hear no other sound.

With the Armi San Marcos, my old one, it's a different story. I hear three clicks: 1) half-cock, 2) full cock and then 3) another click. The last click is achieved just after full cock.I pull the hammer slightly further back and I think the bolt is locking in place. When done slowly, I can even see the cylinder move and lock into place. It is not a large movement but the movement is clear.

This is not noticed when strongly cocking the revolver because one is easily moving past full cock. This is noticed on two occasions: 1) a very slow, easy cocking action and 2) when someone with less hand strength cocks it and stops when it clearly reaches full cock. At full cock, the second click, the hammer will fall if the trigger is pulled.

As for the cylinder, there is noticeable wearing on the lead in to the chamber notch. This is always towards the rear (towards the handle) and does not cover the entire lead in depression. There is a slight burr developing on each of the cylinder notches on the exit side. Sorry, don't have all my terms down. Only between two of the six cylinder notches is there a scratch from one notch to the other.

Been reading up on this issue trying to figure out what is the problem. Short hand, wide bolt, weak spring, etc...? Not sure if this is the right forum to post this. If I need to repost under handguns just let me know.

If you have any idea what is going on here or how to fix it, I would appreciate the advice. Thanks.

Todd

 

[crockett]

Well I would begin by saying that all the parts interact so changing one thing to correct a problem could possibly throw off the timing in another area. I'm not avoiding the issue- just trying to point out that it is often best to spend a lot of time trying to determine the cause of the problem- the actual work to fix the problem- that's the easy part; the hard part is figuring out what's wrong.
The general notion is that after the bolt pops up to lock the cylinder that the hammer should only move back a hair or two, no more than 1/16" to 1/8" at most. Any farther back is stressing the inner parts. The bolt popping up is another sound and lots of folks think C-O-L-T for the four sounds. If the bolt is not popping up on other chambers as well- then- the hand is POSSIBLY be the problem and the hand might be too short. The channel the hand slides up and down might be sloppy- causing a hand of proper length to bend/twist side ways. Alternatively, if every other chamber has the bolt pop up correctly- then- you need to see how far back the hammer moves on the other chambers before locking. If the cylinder locks an instant before the trigger goes into full cock- then things are pretty tight, so tight that just a little difference in the offending chamber is causing it not to lock. BUT, if the other chambers have the bolt pop up and then the hammer still needs to be puled back 1/8" to obtain full cock- them there is a lot of margin on those other chambers so I might then think about the problem being in the racket, etc which would effect just that particular chamber. There could be a bur, etc on that part of the racket which is causing only that chamber not to lock up before full cock.
Fortunately the lock work on a percussion is the same as on the later Peacemaker and there are several good gun smithing books around on the Peacemaker. I always refer to these type books when I have a problem.

 

[crockett]

P.S. There is a cam on the hammer. The bolt has a split tail. If the hand is too long OR the tail on the bolt isn't adjusted correctly- the hand will start pushing the cylinder before the cam acts on the split tail of the bolt- forcing it down. This could cause the wear on the exit side of the cuts.
You might have too short a hand if two chambers are not locking up before full cock AND you might also need to slightly bend the tail on the bolt.
Wait for a few more responses before doing anything.
Dixie Gun Works sells oversized replacement hands.

 

[paleryder]

Thanks, Crockett. Yes, it's a little much and I'm getting my head wrapped around the inter-relationship of the parts and their working.I'm going to do some reading like you suggest.

The bolt is rubbing the cylinder on the bolt's trailing edge, not it's lead edge. A groove was even starting to form on the trailing edge of the bolt. So, as the bolt enters the lead-in to the cylinder notch the back edge of the bolt is catching. This has caused rough areas on the lead in and the bolt. This must also be the part of the bolt that is catching the far edge of the notch as the cylinder cycles after shooting.

I used a stone to try and smoothing the offending bolt edge. This seemed like the easiest and least intrusive remedy. From what I can see, it should not affect the bolt's ability to lock the cylinder at all. I will try and smooth the cylinder notch lead-ins so I don't redamage the bolt.

There was a burr on top of the hand. In fact, there are quite a few burrs on the ASM. Some may not be offending; some may. I'm not sure which is which yet.

Whether or not some other problem is causing this rubbing is another matter that I'll investigate if this doesn't solve the problem.

I don't hear the four clicks. I don't hear the bolt dropping like I do on the Pietta. On the ASM, there is nothing except half-cock, full-cock and the bolt locking. On the Pietta the bolt release and the full cock must be dead on because I only hear one sound. Perhaps the bolt not dropping enough is the reason for the burr forming on the far edge of the notch.

So far, I am impressed with the Pietta. It appears to be put together much nicer than the ASM I got from EMF 20 years ago.

Your thoughts are appreciated.

Todd

 

[paleryder]

Okay, this is odd. The observations I made before may not have explained what happened at the range. While cycling through the chambers, at one point the cyclinder quit revolving. I cocked the hammer several times and it would not move. All of a sudden, it moved. I cycled through several times counting the chambers to see if there was a problem with one of them. Didn't happen again. Hmmm?

While I think there is a timing issue, it may not be what caused the non-firing incident at the range. I am wondering if the cylinder just didn't turn.

My eyes were not playing tricks on me and the cylinder would not turn with several attempts to cock it. I couldn't replicate it once it got moving again. Why would something like this be intermittent?

I've heard/read contradictory things about ASM Hartford models sold by EMF. One article says there were top-of-the-line while other say they were poorly put together. One artilce suggested it mattered when the revolver was purchased because the quality fluctuated.

May it be blessed,
Todd

 

[gmarc]

Todd

Quite often, it is assumed that a "timing problem" is the fault of the cylinder hand. More often, there are issues with the following:

1. Excessive cylinder end-shake. This is easily diagnosed by seeing if you can move the cylinderback and forth while cocked and uncocked. There should be essentially no movement. If there is, the hand will not engage properly or consistently. This is common with the Italian imports.

2. Incorrect alignment of barrel with cylinder..check this with a diameter specific range-rod.

3. Excessive head-space. On revolvers, this is usually taken between the rim of the cartridge and the recoil-shield on the frame. I'm not sure with cap-n-ball guns.

On many old style revolvers, it was normal for the cylinder bolt to contact the area adjacent the cylinder notches during rotation. On others, the bolt did not engage until the hammer was to the rear.

 

From your description of fast cocking and skipping time, slow cocking and going into battery it sounds like the hand spring is weak. On open top colts the hand actually acts as a brake to slow the cylinder down and allow time for the bolt to drop into the cylinder stop. It could also be the bolt/trigger spring getting weak.

Every import cap and ball I own I've had to do a little fine tuning to. I've never owned a ASM, but I've had good luck with Ubertie's, pietta's generally have soft internals that wear a bit faster than others.

Best thing is to get a copy of "Gunsmithing Guns of the Old West" Got a lot of good info on mid to late 1800's firearms.

 

[paleryder]

Thanks to the both of you. There is some movement of the cylinder, more in the ASM than the Pietta. I might try replacing a spring to see if that has and affect, positive or negative.

I'll search around for the recommended book. I find this quite interesting. I'm hopeful just to learn how these things work. I'm sure I'll figure it out eventually. While it looks overwhelming at the moment, there is a limited number of possibilities. It's possible that it's not something I can handle. I did try to get some parts from VCI but there had very few parts available for the ASM. I got some parts from similar guns and will probably use the ASM to learn some "Old West" gunsmithing. I have one book that I purchased 20 years ago that I've been looking at by Sam Falada, I think. I understand there's more available now. I am going to have to get some tools though.

I appreciate the help.

May it be blessed.

Todd

 

[gmarc]

Todd:

The above mentioned book is a goldmine of info on the old S/A revolvers. I have spoken with Dave Chicoine and he has done repair work for me.

He is, I think, the most knowledgeable revolver smith out there. He is especially hip on the S&W top-breaks.

Those old revolvers had a great deal of hand-fitting done to them, which is tough to make pay on a price-point controlled revolver. Some designs don't lend themselves to artisan production lines where the craftsmen aren't particularly well trained. This was very true of the early production of the Schofield replicas that had all manner of internal problems.

ASM had to ultimately stop production because their revolvers had so many problems. Some argue thet revolvers are arguably tougher to make then auto
pistols, just because ogf the design.

 

[paleryder]

I contacted Dave Chicione and he has a few copies of his book available but not many. I'm getting one.