Mysterious Scoring

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Last Post 24 December 2022
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Aaron posted this 23 December 2022

Can anyone suggest what on earth caused this scoring at the rear of this revolver cylinder? I purchased he gun used in the late 80's and this ring was on it when I purchased it. It detracts from the gun when viewed up close but when the revolver is viewed at arms length, the charcoal blueing makes it appear as a gold ring around the cylinder. This was my first Cimarron revolver and I really like this revolver. Bullseye ejector, BP frame, and beautiful case hardening.

I know this is NOT bolt drag since you can see the bolt race forward of this scoring. The frame does not impinge on the cylinder and there is at least a 10 thou gap there. No screw face is there. I just can't imagine what may have caused this scoring which is around the entire circumference of the cylinder. Suggestions?

With rifle in hand, I confidently go forth into the darkness.

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delmarskid posted this 23 December 2022

That’s weird.

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Tom Acheson posted this 23 December 2022

Maybe not so weird…

I have (2) S&W N-frame revolvers, a Ruger Vaquero and a Dan Wesson revolver. All of them have that line around the cylinder perimeter. I do have one other N- frame Smith that has not been fired and that ring is not present.

My “theory”, look at the flat surface of the lower part of the frame in the cylinder “window” and there might be a raised moveable “tab” that recedes when you cock the trigger, with the cylinder removed or swung out, so you can watch it. That tab lines up with the notches in the cylinder. As the gun is cocked the cylinder is rotating and it drags slightly across that tab, even though the tab is recessed, to let the cylinder rotate. That tab raises up locks into the notch on the cylinder to retain the cylinder in the correct place for the upcoming shot.

One of the pitfalls of hoping to have a revolver look pristine after use. Maybe be more concerned with the residue building up on the face of the cylinder, that is really difficult to remove. You don’t see it as much on a blued revolver but it sure shows up on a stainless cylinder.

Tom

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Aaron posted this 23 December 2022

Tom, you are describing "bolt drag" which is clearly identifiable on this cylinder around the cylinder at the bolt notches. I am asking about the other ring at the very rear of the cylinder. As you point out, bolt drag is present on almost 98% of fired revolvers. Action timing must be PERFECT for a cylinder to not exhibit bolt drag. Again, I am asking about the other ring.

With rifle in hand, I confidently go forth into the darkness.

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Tom Acheson posted this 23 December 2022

Aaron,

I see what you are talking about. That is interesting. Fixed sights so no rear sight screw protruding downwards. The loading gate can’t be causing it, at least my Vaquero doesn’t indicate that.

Will be curious what others postulate.

Tom

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sluggo posted this 23 December 2022

Maybe a piece of sand or grit got lodged between the cylinder and frame and scratched the back of the cylinder as it rotated?

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RicinYakima posted this 23 December 2022

I think you are correct. Fouling, piece of jacket, etc. wedged between top strap and the cylinder. My Cimarron has very little clearance between the cylinder and top strap. When cleaning, it is always full of powder fouling, bullet lube and dirty stuff.

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delmarskid posted this 24 December 2022

I’m leaning toward the captive crud theory. Looking closer at the rearward ring there seem to be a couple less visible marks parallel .

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Aaron posted this 24 December 2022

It has to be captive goop.

Cocking in a holster - Nope.

Lying on a bench - nope.

Dragging along a surface - nope.

Ah.....could have been whilst cleaning the cylinder with a crud infested rag while cylinder removed. Holding a rag in one hand and rotating it on the base of the cylinder to clean it perhaps. There may have been a rock or a metal shaving embedded in the rag.

Thanks for all the brain waves on this. I was just curious and thought one of you gray beards may have seen something like this before.

With rifle in hand, I confidently go forth into the darkness.

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MarkinEllensburg posted this 24 December 2022

Possible that previous owner used a clamp on scope mount with poor fitting. Looks like a good use for some cold blue.

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Aaron posted this 24 December 2022

I had thought of a touch-up pen or some other cold-blue chemical but unfortunately, this is a charcoal blue finish. I can't locate any charcoal blue touch-up solution on Brownells or other supply locations. Does anyone know of a touch-up pen or solution which can be used on a charcoal blue finish?

It's this revolver. A dark blue touch-up pen or solution would be drastically different. Of course, I could pimp it out with a tri-tone finish.

With rifle in hand, I confidently go forth into the darkness.

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Premod70 posted this 24 December 2022

The slop in the cylinders ride on the pin and the clearance of the cylinder to the frame is in need of additional clearancing. A little wet/dry sandpaper applied to the frame in the infected area should have the revolver running smooth, good luck.

Forrest Gump is my smarter brother.

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Aaron posted this 24 December 2022

Thanks Premod70. Fortunately this revolver is tight. There is no end-shake, headspace is minimal, and frame to cylinder clearance is satisfactory at 20 thou both at 12 o'clock and 6 o'clock. Axial alignment is true as well. Sounds like the foreign material theory is the actual culprit.

With rifle in hand, I confidently go forth into the darkness.

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