Progressive DEPTH in original Spencer rifling?

[El Supremo]

Hello:

A post yesterday, 19 JUL 16, on the N-SSA Forum about progressive depth rifling contained a comment that "Spencer rifles (writer did not specify carbines) had rifling that was deeper at the breech end than at the muzzle".

While this form was used on several U. S. military rifles in the 1800's, I have never before seen this mentioned , as it applies to Spencers.  

So, would our Spencer experts please help the rest of us and share IF IT IS TRUE, and any related info.

Many thanks,

El Supremo/Kevin Tinny

[Blair]

Hi Kevin,

Thanks for the PM regarding this subject.

I did not reply to this original question, simply because I don't know.
I've never had reason to check for progressive depth rifling in any Spencer. This is mostly due to the very different type of ammunition intended for use in the Spencer compared to the hollow based bullet used in the muzzle loading firearms.

I think Carolina Reb.  suggested that Slugging the barrel at the breech of a Spencer can be a problem.

I have a Burnside contract '65 carbine barrel that I removed. I could check this one out pretty easy, but as I said it is a carbine and a contract model, I was not sure that it would have given you the info you were looking for? Especially regarding the earlier Rifles.
My best,
Blair

[El Supremo]

Thanks, Blair:

Your response IS helpful because it indicates that even with your depth of knowledge, you are unaware.

I am still hoping that Herbert or Arizona Trooper might know something.  So far no one can point to any factory specification information; even though Carolina Reb found progressive depth grooves in three of his rifles.

Am on the alert for any historical info that adds to/clarifies Marcot.

It is amazing what you and others here know.  Many thanks.

Most respectfully,
El Supremo/Kevin Tinny

[Trailrider]

While I never checked the rifling depth per se, but I have measured the groove diameter of several M1860 carbines, and they averaged about .545" at the breech end and .535" groove at the muzzle. I wound up using .538" dia. hollowbase bullets (Lyman 533476AX cast with Lyman #2 equivalent), with 8.0 gr (then) Hercules Unique.  If you look at the sectional density of this bullet, compared to a .45 LC 250 gr. bullet, they are very similar, as is the case capacity of .50-70 cutdown brass.  Accuracy was pretty good, depending on my eyesight and lighting conditions.  So, yes, the rifling depth is shallower at the muzzle than the breech end.

[El Supremo]

Nice to have your helpful info, Trailrider:

Now, thanks to you, we know the same thing has been observed in 1960 Spencer carbines. 

Regards,

El Supremo/Kevin Tinny

[Blair]

Just finished a very long, yet enjoyable, phone conversation with Kevin.
Talked about many things, not the least of which was the development of progressive depth rifling.
It was not specific to the use of this type of rifling in the Spencer (I have no knowledge in the specific area).
It was more about a history of why and how progressive depth rifling evolved. Based on my knowledge of firearms development of the time period in question.
I am sure Kevin and I will do this more in the future.
Thanks. I had a great afternoon!
My best,
Blair

[El Supremo]

Hello, Blair:
Nice to have you back there on the pedals.  Had a brief telephone chat with Larry Romano this noon.  All this about progressive depth rifling in the Model 1860 Spencer rifles and carbines is news to him.  All he had measured was twist and bore.  And he went to a faster twist.

Still hoping that Herbert might say something.

Crossed my mind that the relatively expensive equipment to rifle this way might have been left after the Harper's Ferry work by Robbins & Lawrence.  If so, was that machinery in the Spencer/Chickering Building or maybe the barrels were rifled elsewhere by a vendor using the R&L machinery.  Why Spencer would have imparted this style rifling that was more expensive and not better is a mystery, to me.

Regards,
El Supremo/Kevin Tinny

[Blair]

Kevin,

I don't believe it has anything to do with the Kindle, Robbins & Lawrence, or the Robbins and Lawrence contracts.
However, the same "Lawrence" was very much involved within Sharps development of the pellet priming system.
It also seems as though this same "Lawrence" worked very closely with Spencer while he was setting up tools, dies and jigs for his Government production line.

The usage of progressive depth rifling may have been much more prevalent in the US at the time than I had ever suspected. But the bullet design for the breech loading firearms compared to the muzzle loading firearms is what would, and has made me suspect to the validity of progressive depth within breech loaders.
My best,
Blair

[Trailrider]

Kevin,

(snip)
The usage of progressive depth rifling may have been much more prevalent in the US at the time than I had ever suspected. But the bullet design for the breech loading firearms compared to the muzzle loading firearms is what would, and has made me suspect to the validity of progressive depth within breech loaders.
My best,
Blair

I wonder, if progressive-depth rifling was used in muzzle loaders, if the same machinery might have been used for the barrels for breechloaders?  We know for certain that progressive depth rifling was present in Spencer M1860 Carbines.  "Why" is another question.

[Will Ketchum]

I wonder, if progressive-depth rifling was used in muzzle loaders, if the same machinery might have been used for the barrels for breechloaders?  We know for certain that progressive depth rifling was present in Spencer M1860 Carbines.  "Why" is another question.

I don't know about "progressive depth" in muzzle loaders but I know that in some  they used a "gain twist" that started slow and became faster towards the muzzle.  I custom flintlock has such a barrel.

Will Ketcum

[El Supremo]

Hello: 

Modern high-grade barrel makers observe that "gain twist is rediscovered about every ten years".

The latest development in rifling is not the form, rather it is the precision and accompanying variations that CAD/CNC rifling machines can impart.

Interesting that one very respected modern barrel maker shared that he went to an 0odd number to lands and grooves so that it would be harder for the buyer to accurately measure groove depth and make frivolous complaints.

These expensive CNC rifling machines have supplanted the traditional arsenal surplus Pratt's that are still doing good work.  Now, top level modern competitive shooters demand all sorts of things such as 2 to 3 tenths breech-to-muzzle taper and twists that have a minute amount of gain, often .1" over 26"-30".  These machines routinely hold 2 tenths in cross section over the full length. 

I know a shop that has CNC rifling gear.  They can do progressive depth grooves in gain or constant twist of any rate, even gain that switches to constant  twist near the muzzle. 

Frankly, that's over engineering for skirmish shooting.  These shops agree that the form of the rifling, number of and shape of the lands/grooves and whether the rifling is cut or buttoned, doesn't matter, so long as the steel is correct (4140 or 4150 UNLEADED TO AVOID WEAKENING INCLISION "STRINGERS"), tolerances are very tight AND the barrel is stress relieved and correctly hand lapped - which always involves grooves and lands.

Regards,

El Supremo/Kevin Tinny

[Trailrider]

The wonder is (and as an engineer it has always fascinated me) that gun designers and manufacturers back in the CW and post-CW were able to produce the kind of intricacy and precision that they did, given the state-of-the-art at the time. Master gunmaker John Moses Browning produced his first marketable guns (the Single Shot...later the Winchester HiWall) using files, cold chisels and breast drills!    While we think of Christopher Spencer just as the inventor of the Spencer Repeating Rifle, he also was responsible for developing the automatic screw machine, and even was taught to fly a plane by his son in the early part of the 20th Century!

[Snakeeater]

Robbins & Lawrence have always been somewhat of a mystery to most people. But they were not just gun-makers or tool-makers but also produced not only railroad cars but also the different railroad track rail gauges used throughout New England, and virtually everything else needed by that industry. Indeed, had they not been so diversified in manufacturing to have stayed away from the railroad industry, they probably would never have gone into receivership. The only profits they made was from producing guns. Samuel E. Robbins was a salesman, and he had earlier teamed up with Benjamin Flagg who had been the superintendent of the Asa Waters Armory. Benjamin Flagg, of course, invented the milling machine, and in 1835 the firm Robbins & Flagg of Millbury built a machine for milling of the curved surfaces of lock plates for Springfield Armory. It was this machinery which facilitated manufacture of lock plates and other musket furniture on the interchangeable plan for the Model 1835/40 flintlock musket.  Indeed, the first engine built to power the milling machinery at Springfield Armory was built by Otis Tufts of Boston under contract in 1843 in preparation for manufacturing the new M1842 percussion musket enabled by Flagg's machinery. 

In 1841, following the death of Waters' armory founder, Asa H. Waters Jr. (1769-1841), his son, Asa H. Waters III (1808-1887) entered into partnership with Benjamin Flagg (1807-1864), under the firm name Flagg & Waters, until Thomas J. Harrington joined the partnership when the firm changed its name to "A. H. Waters & Co." That firm operated for 25 years until the partnership was dissolved in 1867, when Flagg's son (George H. Flagg) joined the firm, took the old cotton mill property of the old firm and continued the business of cotton manufacturing, their mills being known as the Millbury Cotton Mills. Although Benjamin Flagg had entered into partnership with William Glaze and James Boatwright in establishing Palmetto Armory, the Waters machinery evidently remained in Millbury.

The history of the Robbins & Lawrence Company begins about 1838, when Richard Smith Lawrence came to Windsor from the neighborhood of Watertown, N. Y.  N. Kendall & Company, was regularly making guns at the Windsor prison. Robbins would later join Richard Smith Lawrence in 1844 in establishing the firm of Robbins, Kendall, and Lawrence (formerly Kendall & Company) which in 1850 was reorganized into Robbins & Lawrence.  As you may be aware, Robbins & Lawrence also started the Sharps' Rifle Manufacturing Company in 1851, and are credited as the first firm to initiate the manufacture of firearms on the interchangeable plan. Ever wonder where they got the idea for this method? In the winter of 1844 was when Robbins came to them and told them that the Government was in the market for 10,000 rifles. The matter was talked over, a partnership formed, and a bid sent to Washington. They bought land, built a shop, and bought or made the necessary machinery. It was in the performance of this and the subsequent contract that many of the early machine tools were developed. In 1848 Kendall sold out his interest in Robbins, Kendall & Lawrence, and in 1850 Robbins & Lawrence Co. was formed as a reorganization of Robbins, Kendall & Lawrence.

The firm failed in 1856 and the plant and equipment were bought in 1859 by Ebenezer G. Lamson, who then organized Lamson, Goodnow & Yale retaining Samuel E. Robbins as superintendent. This firm later became E. G. Lamson & Co., Windsor Mfg. Co. (1865), then was reorganized as Jones, Lamson & Co (1869) and finally Jones & Lamson Machine Company in 1879. In 1889 the present Jones & Lamson Machine Company moved to Springfield, Vt., where it now is. A number of the old mechanics and foremen, who had homes in Windsor at the time the company moved to Springfield, took over the old shops and organized the present Windsor Machine Company which now manufactures the Gridley Automatic Lathes.

[El Supremo]

Great job of sharing, Snakeeater:

The puzzles, with the help of Blair, are:

WHY, with Spencer's closeness to Sharps that knew progressive depth rifling made no difference in breechloaders and therefore did not use it, would Spencer incorporate such a frivolous feature, when the machinery and manufacturing cost more?

The question of where the equipment came from is another unknown.

I see nothing in Marcot about any of this, especially a government requirement for this form of rifling.
Only a generalization that the "test sample" be duplicated. 

I wonder who made the rifling machinery that Spencer used?  Was it the Robbins & Lawrence stuff left after the musket conversion work?    Maybe Spencer bought used equipment and  knew where to find the skilled operators. 

As Blair shared:  Because this form was unnecessary, historians never "looked for it".

Herbert:  Does any of this fit your knowledge, please? 
Many thanks to all.

Respectfully,
El Supremo / Kevin Tinny

[Herbert]

I have found the 1860 model Spencer to have larger diameter lands at the breach than at the muzzel ,latter models the depths seems to be the same

[El Supremo]

Tx, Herbert:
Know you are preoccupied.  Tx for taking time to respond.

Will await PM on clarification of depth of grooves at breech vs. muzzle.  NO RUSH.

All the best,

Kevin

[Blair]

Kevin,

I tried calling you about 1:30 PM. Left a message.
Should you return my call, I will try to get back to you before the evening is over. I have company coming in (maybe today) and I'm not sure what we will be doing.
This is a very old friend of mine. We have both been involved with shooting and building ACW firearms for well over 40 years, a very long time. Perhaps he will have info to add to the conversation?
My best,
Blair

[El Supremo]

Thanks, Blair:

As you observed during our conversation yesterday, with Herbert's confirmation and those of others about progressive depth riflling in several 1860 Spencers, it is now time to try to learn serial numbers.

Especially important is your info that the depths were more likely .003" or so greater at the breech than muzzle instead of .005" or more, which greater amount was in British Enfields, not U.S. arms of the same era.

Nice to know also that progressive depth was developed by the British for the expanding SKIRT projectile and is not needed for a SOLID based bullet.

I will contact "Carolina Reb" for info on the three 1860's that he has seen and keep all of us posted here.

Tx, again, Herbert.

Regards and all the best,

El Supremo/Kevin Tinny

[Colt Fanning]

Hi,
I have a model 1849 colt revolver with a 6 in. bbl. ca. 1860 that has gain twist rifling.
Regards
Colt

[El Supremo]

We haven't been idle, everyone:

CAS/SSS and N-SSA members have been very thoughtful to privately share with me that the serial numbers of their measured RIFLES range between 16XX and 89XX, and have deeper grooves at the breech.  It seems that 7,300 RIFLES would indicate that the progressive rifling form was extensively used, at least in rifles.

We are trying to find someone with an EARLY Navy rifle that can share if the same deeper grooves are present.

One contributor shared that Sharps barrel BLANKS may have been used on early 1860 RIFLES. 

One expert doubted that the Sharps blanks would have come with progressively deeper grooves because Sharps "knew" that it didn't help the ring-tail, non-expanding base bullet.

As one said, progressive DEPTH grooves were used for HOLLOW base, expanding skirt bullets and did NOT help solid, flat base bullets; so why this form was used by Spencer remains a mystery.

No one seems to know which company made the rifling machinery used by Spencer.  There are several possibilities, including Ames, Pratt & Whitney, LG &Y and Robbins &  Lawrence, with some smuggled to the CS,  British machinery also being mentioned. 

An expert shared that the remaining Spencer company papers are in the Cody Museum, but are is such disarray that he estimated a person could spend weeks trying to review them.

Does anyone know WHO donated the Spencer papers to Cody? 

Anyone have groove measurements for 1860 CARBINES, please?  Thanks.

I have two more Spencer experts to reach.  PM'd one and am waiting for contact info on the other.
More to follow.

Regards,
El Supremo/Kevin Tinny