I have a few Chiefs Special and Terrier examples living in the stable. I have a recent addition, a nickel plated baby Chiefs Special. I was bragging it up a bit to a fellow collector, mentor, and well known authority on these little things, and explaining where the "N's" are. I didn't see one on the cylinder under the ejector star, but my mentor said 'check again'. I did, and there it was. I looked right through it on first inspection, but perhaps had a reason or two to do so. My eyes aren't the greatest these days, and there is a dimple that was applied over top of part of the N.
This prompted me to look at a few other Chiefs and Terriers to see if the dimple is always there. Perhaps half of mine have a dimple that is obvious. So this prompts the question "What is the dimple for?" Do your revolvers have a dimple? And, of course, what purpose does it serve.
I will offer a guess on purpose.... Is it to test heat treating/metal hardness? (I offer up that guess as I have seen some USGI weapons sporting a similar dimple and my understanding is that it was a test for hardness.)
I will attach a few pictures, and I welcome your thoughts related to what and why they are!
(All three examples are nickel. Is there a correlation there, or is it coincidence?)
And notice that two out of three touch the "N".

Here's one on a Terrier, likely dated around 1953, at about 10:00 under the star.

IMG_3808.jpg


And another Terrier at about 12:00
IMG_4478.jpg



and a Chiefs Special at about 5:00
IMG_4856.jpg

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NRA Endowment Member

Not sure what the dimple would serve but my 36 nd, 13-4 and 60-15 have dimples while a 60 nd and a 10-5 don’t.
Wonder if they are kind like inspection marks but very faint and no burr like in the occasional N stamps.

When I worked in the GE central A/C factory in Tyler, one of my jobs was heat treating valve bodies...After processing a couple of hundred I tested 4 or 5 of them for hardness on a Rockwell scale...The ones I tested each had that mark from the test...I imagine cylinders were heat treated and tested in much the same way, which might explain why some have the mark and others don't......Ben

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Cogito, ergo BOOM!...

Not on my M649.

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Come and take it!!

Not on my 60, R293xxx series. That hardness test theory has some merit...

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Even older, even crankier....

I'll bet Steelslaver can explain how the Rockwell hardness test measures the dimple in the metal. Truckman too. I'm sure he has the gauge.

The one I used 50 years ago was mounted solidly to a steel table near the furnaces and quench tanks I used, probably so mounted to prevent their being relocated to local pawn shops...Steelslaver would be the guy to explain the intricacies of the operation......Ben

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Cogito, ergo BOOM!...

They are either inspection marks, proof marks or metal hardness testing marks. While they more than likely test the metal's hardness here and there, it is very unlikely they test many of them. They are probably heat treated in batches and probably test 1 or 2 (if they suspect anything) from a batch. Just guessing of course but I would never expect each one tested.

I think Mr. Jinks said the gun is "pricked" after test firing.

Bill

All firearms are test fired before being shipped. After they are fired, they are stamped with a prick punch. Most are punched in the "window".

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Don Mundell

The way Rockwell testing works is a certain load is placed on a point and the depth the ""dimple" the point makes give you a value. The type of point and load vary by the scale used. Rockwell B does use a round ball while R A and RC uses a diamond point as shown in this chart




The frame, cylinder and barrel readings I took some time ago were so low on the RC scale that I went to the ball and B scale. All of them were in the low 20s using RC and in the mid 90s RB. Just a bit harder than mild steel.

There is a lot more to it than hardness. But, if similar batches of steel were HT in the same way, hardness testing of a few of the pieces, would confirm that you got consistent results.

But, at this point with mills being able to produce verifiable certified alloys, digitally controlled ovens, most likely containing inert atmosphere to avoid surface decarb, The results should be very consistent as long as nothing odd happens during the HT cycles. But, the real QC takes nothing for granted. Butt, then again the current S&W QC down stream from forging and HT has been questionable as of late.

It’s pretty obvious a gun has been fired-the cylinder face has carbon rings on the very first shot. Because of that I kind of doubt they would dimple mark it. Just so obvious to see after firing I can’t believe they would mark it again for that!

I used the C scale on valve plates, but I cannot recall the values I needed 50 years later......Ben

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Cogito, ergo BOOM!...

As somewhat of an aside, my take on heat treating is it's the suspenders-----as in "belt and suspenders".

I have a rather interesting letter from D.B. Wesson---from March, 1934---to a customer inquiring about heat treating. That of interest is the steel "as it comes from the mill" is entirely adequate for every gun they make at the time----without ANY further treatment.

So what does that mean? Well, one of the guns they made at the time was the 38/44 Heavy Duty/Outdoorsman---made for some souped-up .38 Special loads which approach the soon to be announced 357 Magnum when it comes to that which makes "Nervous Nellies" what they are.

I'll say it again------"the steel as it comes from the mill" is good to go for any gun they make at the time. For today's "Nervous Nellies", I'll tell you he also said "-------we also prefer the very much improved (margin of safety) the treatment provides." That translates to they went ahead and treated the cylinders of those romping, stomping big guns anyway.

Given the fact their Mommies didn't raise any dumb kids, they did that because they didn't want to be spending any of their time talking with pesky lawyers about damaged guns---or damaged customers---and they still don't----and never will.

The bottom line of all this is those pesky lawyers serve a valuable purpose by keeping folks on the straight and narrow----and those dimple marks just might be a way of demonstrating that to the folks on the juries---if/when it might come to that.

See Risk Management 101 Remedial for further enlightenment.

Ralph Tremaine

Oh---and Risk Management 101 Remedial tells us the best way to manage a risk is to avoid it in the first place. A rather obvious way to do that is to stop making guns. Given that is contrary to what they had (and have) in mind, they made them as safe as possible---then and now.

I also understood from Roy that the dimple was to indicate the gun was test fired. I have several N frames, pre war and pre 1961 with the dimple in the bottom front corner of the cyl window. I have a few small frames with the dimple on the left side of the grip frame near the top.

I never noticed any on the cylinder under the extractor star. I’ll have to check.

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Jim
S&WCA #819

It is not for you. It was to show that it was test fired. Back in the day, all 5/6 cylinders, or full magazine were test fired. I know because I have a friend that did that job for over 30 years.

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Don Mundell

How's his hearing?

I ask because hearing protection back in the day was less than effective, and my hearing was deemed deficient following a physical exam for my pilot's license---at age 40. The doctor said my hearing was damaged (loud guns and loud cars)---and he described it in doctor talk. I asked what that meant in plain English, and he said, "You haven't heard any birds sing lately!"

He was right.

Ralph Tremaine

Looked at my older j-frames. My 60, 36, and 38 have no dimples. All are no dash, so they are "old". My newest, a 637, has one.

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Heavily armed old man.

The only constant about S&W markings is that there are always exceptions.

The earliest two hand ejectors I have are two triple locks and both are dimpled with a tiny P in the cylinder window.

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Jim
S&WCA #819

And then there are folks like me.

Dimples?!!

It never occurred to me to look---and if I'd noticed one, I wouldn't have paid any attention to it whatsoever!!

Numbers---letters?? I saw them, knew pretty much what they were, and went on about my business.

Ralph Tremaine

A friend, fellow collector, and fellow Forum member raised an interesting point. If the dimples are a hardness test, wouldn't the results be a bit skewed by doing the dimple over top of another stamping such as the "N" as seen in several of my pictures? From what I can see, it appears that the N was there first, then dimpled. I was really leaning towards the dimple being a hardness test, but that throws a wrinkle on to my sheet.
So far we are all guessing.....

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New Model 640 - yes, flat latch Model 36 and nickel Model 49 - no.

Remington Rand 1911A1 - yes.

Attached Images

IMG_0414.jpg (122.2 KB, 13 views)

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“What you got, ain’t new.”

Well I finally got the chance to refer to my notes and this is what i have:

PUNCH DOTS after test firing at the factory:
These marks are made by the test shooters to show that the gun had gone through the range test firing.

A tiny P was the first mark used after test firing. You will see it on the top break revolvers generally under the cylinder and in the front lower corner of the cyl window on Triple Locks. The British Svc .455 Revolver and the early 1917 Army can also have a P in the front lower corner of the cyl window, or no marks at all. Later, two tiny round punch marks can sometimes be found on the left side of the grip frame’s front strap, near the top, just below the stock circle under the stocks. Also can be a single punch mark on left side grip frame. A single dot over the B for blue on the right side grip frame has been observed.

Beginning in the 1950’s period, two dots will be found in the front lower corner of the cyl window or single dot on cylinder under the extractor star.

My Triple Locks have the punch mark in the cyl window but it’s not a dot; both of mine have what can only be interpreted as a tiny P.

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Jim
S&WCA #819

When I inherited my grandfather's old Colt revolver, I noticed similar dimples but never thought much of them. Now, your observation has me wondering about their purpose too.

I collect Colt SAA revolvers and have some of all three generations. But I haven't observed any punch dots (dimples) nor have I read anything about them being observed on Colts.

Do you remember where on the gun the dimples are located?

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Jim
S&WCA #819