5.10 Reflections on Centaure Conversions and the Open Top

Chapter 5 – Centaure Conversions the Next Level of the Evolution?

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5.10

5.10.1

5.10.2

5.10.2.1

5.10.2.2

5.10.2.3

5.10.2.4

5.10.3

5.10.4

5.10.5

Reflections on Centaure Conversions and the Open Top

The Gold Standard: How Do Measurements of Modern Colt 1860 Cap & Ballers or their Conversions Compare to Originals?

Working Assumptions

Original Colt 1860 Armies, Re-Issues and Replicas

Original and Modern Colt 1860 Army Thuer Conversions

Original and Modern Colt 1860 Army Richards Conversions

Original and Modern Colt 1860 Army Richards-Mason Conversions

Caveat Regarding Modern Breechloading Colt 1860 Army Conversions

Conclusions

Yes, we can – But Do we Want?

5.10.1

The Gold Standard: How Do Measurements of Modern Colt 1860 Cap & Ballers or their Conversions Compare to Originals?

Now is the time to ask the important questions about the dimensional accuracy of the reproductions. Which ones are close to the benchmark, to that gold standard set by the original Colt Armies from yesteryear? Are our modern Colt 1860 Armys manufactured by the replica industry, or custom-built conversions, within the ranges of their 19th century predecessors as assessed by a number of the FRiends Of the Centaure Society (FROCS) community from around the globe? Or, as provided by R. Bruce McDowell in his sought after conversion bible from 1997 titled A STUDY OF COLT CONVERSIONS AND OTHER PERCUSSION REVOLVERS? What is the impact of production tolerances back then and today?

To answer these questions samples of

# Colt 1860 Army pattern percussion revolvers: Reference original Colt 1860 Army and

# Colt 1860 Army pattern conversions: Reference original Thuer, Richards, Richards-Mason conversions were measured in a standardized manner with digital calipers. This task was accomplished within a few weeks thanks to the international network of the FROCS community. These three parameters or key dimensions were considered important and were compared:

# Diameter front of cylinder

# Diameter rebate of cylinder

# Overall height of barrel lug

The sample of the modern Colt 1860 Army percussion revolvers comprised these popular brands and makers, respectively:

Centaure Civilian and Regular New Model Armies (RNMAs) of production 1960 through 1972
2nd generation Colt 1860 Army
3rd generation Colt 1860 Army
Army san Paolo (ASP)/Euroarms
Pietta
Uberti

Their modern Colt 1860 Army pattern conversions included custom built conversions using project revolvers of different makers, and the factory-made variants available from Uberti in Italy:

Dave Anderson USPFA Richards
John E. Gren 2nd gen Colt Richards
Kenny Howell 2nd gen Colt Richards
Karl Nedbal Centaure Thuer, Richards, Richards-Mason
Karl Nedbal Uberti Thuer
R&D 2nd gen Colt Richards
Uberti Richards Transitional, Richards-Mason

5.10.2

Working Assumptions

A healthy human eye will note differences in size of ca. 0,5 mm/.02 in of comparable objects.

Deviations within these ranges are considered regular production tolerances (RPTs), or not significant.
Deviations smaller than RPTs are significant. They mean undersize, printed in bold face in the tables below
Deviations bigger than RPTs are significant, too. They are what we usually refer to as beefed-up or on steroids. Hence, they are printed in bold face type in the tables below, too.

The numbers in brackets like (3) in the Serial number column indicate the number of pistols per manufacturer measured. Numbers in that same column without brackets are serial numbers of individual guns, p in brackets like (p) indicates the year when a conversion artist completed a specific project.

In case more than one gun was available from a manufacturer, measurements were averaged, taking production tolerances into account. Ranges of the measurements are provided as appropriate.

Readings are presented in millimeters (mm) and inches (inch) printed in black or white/red bold type.

5.10.2.1

Original Colt 1860 Armies, Re-Issues and Replicas

This Colt 1860 Army data in below table indicates that most of the three key dimensions of modern Colt 1860 Army pattern percussion revolvers are within RPTs. But bear in mind only three (3) originals were available for reference. If that is OK one should also note the very close tolerances of these 19th century Colts!

Colt 1860 Army

Facts & Figures

mm/inch

Serial number

Diameter

cylinder front

Diameter

cylinder rebate

Height

Barrel lug

Originals*

average (3)

range

41,20/1.622

41,15-41,23/1.621-1.623

38,88/1.531

38,75-38,96/1.526-1.534

47,60/1.874

47,42-47,92/1.883-1.887

Centaure

average (9)

range

40,89/1.609

40,67-41,00/1.601-1.614

38,70/1.524

38,23-38,90/1.505-1.531

47,66/1.876

47,43-47-83/1.867-1,883

Colt 2nd gen.

average (12)

range

40,79/1.606

40,71-40,88/1.602-1.610

38,92/1.532

38,76-39,15/1.526-1.541

47,19/1.858

46,46-47,54/1.829-1.872

Colt 3rd gen.

#217562

40,75/1.608

39,15/1.541

46,95/1.848

ASP/Euroarms

#30478

40,77/1.605

38,89/1.531

48,13/1.895

Pietta

average (3)

range

40,48/1.594

40,44-40,51/1.592-1.595

38,90/1.531

38,79-38,99/1.527-1.535

47,36/1.864

47,04-47,63/1.852-1.875

Uberti

average (4)

range

41,00/1.614

40,49-41,91/1.594-1.650

39,15/1.541

38,86-39,67/1.530-1.562

47,40/1.866

46,99-47,72/1.850-1.879

*Measurements of originals amended by McDowell data

A few selective comments regarding brands or manufacturers are available.

Centaures: Diameters of the front and rebate of the cylinders are below RPTs.
Colt 2nd generations: Height of barrel lug ranges are below RPTs. Only 4-screw frame models are regularly available.
Colt 3rd generation: Height of barrel lug is below RPTs. Only 4-screw frame models are regularly available.
ASP/Euroarms: Height of barrel lug is above RPTs. All of this brand’s 1860 Armies were fitted with backstraps made of brass only.
Pietta: Diameters of the front of the cylinders are below RPTs.
Uberti: Diameters of front of the cylinders and the height of the barrel lug ranges are below, the diameters of the rebate of the cylinder ranges are above RPTs.

$D:\FAP Colt 1860 Army\1-3e94a0b88714f6a3dde6d7c119309a39.jpg$

5.10.2.1_1 Pietta made Colt 1860 Army: Note 4-screw frame and typical bell-shape grip contour

5.10.2.2

Original and Modern Colt 1860 Army Thuer Conversions

Only a small sample of four (4) Thuers was available for measurements, namely two (2) 19th century original Colts and two (2) Nedbal conversions (table below). Therefore, only a few careful comments seem to be appropriate:

Original Colts: The height of the barrel lug of the two (2) original Colts is smaller than that of their percussion brothers presented in the table above, and only just within their respective RPTs. The rebate diameter of the cylinders is above RPTs if compared to the respective percussion originals. This might be an indication that this conversion cylinder was purposely strengthened for the Thuer back then and it was not a converted percussion cylinder.

Nedbal conversions: The measurements of the two (2) Nedbal conversions are almost identical although project guns of different makers were altered namely a 1968 manufactured Centaure from Fabriques d‘Armes Unies de Liège (F.A.U.L.) and a Uberti made Colt 1860 of 1972 production. Regarding their cylinders this was to be expected because they were copied from the same original in the Nedbal collection. The height of barrel lug of the two Nedbal conversions is above RPTs of Colt Thuers but within reference C&B originals!

You find the full story on the Centaure made Thuer in chapter 5.3. Note a few additional details in the table:

Colt 1860 Army Thuer Facts & Figures mm/inch	Serial number	Diameter cylinder front	Diameter cylinder rebate	Height Barrel lug
Originals	average (2)	41,21/1.622	39,16/1.542	47,28/1.863
Nedbal Centaure	#7266	40,67/1.602	38,77/1.527	47,91/1.886
Nedbal Uberti	#14289	40,69/1.602	38,62/1.520	48,03/1.891

$D:\Nedbal-Uberti Colt 1860 Thuer Conversion .44 Thuer\1-P1030854.JPG$

5.10.2.2_1 Nedbal 1972 manufactured Uberti Colt 1860 Army #A14289 with 4-screw frame ltered to Thuer conversion

Italy’s Uberti factory considered regular production of Colt 1860 Army Thuer conversion front stuffers around the turn of the last century. The plan was to launch the conversion. But, also a conversion kit to provide owners of Uberti 1860 cap & ballers with the option to fabricate and shoot their own self-made Thuer cartridges by use of the loading tool. Below is a picture from a period Uberti catalogue of one of their Thuer conversion kit prototypes. Unfortunately, the project has been left on the shelf.

$D:\Uberti Colt 1860 Army Thuer conversion\1-thuer.jpg$

5.10.2.2_2 Uberti prototype of their Colt 1860 Army Thuer conversion kit with loading tool, Thuer cases, bullet mould, conversion cylinder and ring: Note 4-screw frame project pistol

5.10.2.3

Original and Modern Colt 1860 Army Richards Conversions

We are comforted that measurements of the four (4) originals from the 1870s are within RPTs, like those of their C&B brothers. The Dave Anderson/AFA, Nedbal Centaure and Howell 2nd gen. Colt conversions are within RPTs, too. Other Nedbal Richards using Uberti made cap & ballers were not available for measurements.

The Gren and R&D 2nd gen. Colts are off in one dimension only.

The Uberti Richards Transitional aka RII – Uberti does not make an RI – is manufactured as a cartridge gun from the outset. Hence, it is pretty much beefed-up!

Please, note the details regarding these significant deviations from the RPTs in below table.

Colt 1860 Army Richards Facts & Figures mm/inch	Serial number	Diameter cylinder front	Diameter cylinder rebate	Height Barrel lug
Originals	average (4) range	41,24/1.624 41,21-41,30/1.622-1.626	39,92/1.572 39,89-39,99/1.571-1.574	47,69/1.877 47,47–47,90/1.869-1.886
AFA USPFA	1992 (p)*	41,77/1.605	39,57/1.558	47,37/1.865
Gren Colt 2nd gen.	average (2) range	40,87/1.609 40,78-40,95/1.605-1.612	38,85/1.529 38,84-38,85/1.529-1.529	47,42/1.867 47,36-47,48/1.864-1.869
Howell Colt 2nd gen.	1996 (p)*	40,77/1.605	39,65/1.561	47,35/1.864
Nedbal Centaure	#4079	41,61/1.638	40,06/1.577	47,26/1.861
R&D Colt 2nd gen.	1979 (p)*	40,74/1.605	39,45/1.554	47,40/1.866
Uberti RII	average (3) range	42,49/1.673 42,44-42,55/1.671-1.675	41,31/1.626 41,04-41,45/1.616-1.632	48,50/1.909 48,40-48,56/1.906-1.912

*(p): year of custom conversion

Here are some further specific comments regarding the measurements, additional notes and pictures of rare (and not so rare) modern Richards (RI and RII) custom and factory conversions. This data seems to indicate that the U.S. conversion artists prefer the 2nd generation Colt 1860 Armies as project guns for their tasks.

At gunmaker’s Dave Anderson’s AFA Richards conversion of a USPFA fabricated project gun is within ranges of originals. However, the conversion cylinder is of the straight variety and the water table lacks the typical step. These features are also known from Italy’s Armi san Marco (ASM) produced Richards conversion. Rumour has it that there was some collaboration regarding conversions between Anderson and ASM.
John E. Gren 2nd generation Colt 1860 diameters of the rebates of the conversion cylinders are below RPTs.
R&D 2nd generation used Colt diameter of the front segment of the conversion cylinder is below RPTs.
The Uberti manufactured Colt 1860 Army Richards II conversions are way above RPTs in all three (3) measurements!

$D:\AFA Colt 1860 Army Richards Conversion\1-IMG_2194.jpg$

5.10.2.3_1 Anderson’s AFA custom made Richards I conversion using a USPFA production Colt 1860 Army for the project: 3-screw frames; not rebated straight cylinder, forward segment of water table not lowered

$D:\Gren 2nd Gen Colt 1860 Army Richards Conversions #208554 + 204606_1\1-1860 Armies - John Gren Conversions.jpg$

5.10.2.3_2 Conversion artist John E. Gren used 2nd gen. Colt 1860 Armies for this pair of Richards I conversions with 4-screw frames

$D:\Nedbal-Uberti Colt 1860 Army R1 .44 Spez\1-P1030846-001.JPG$

5.10.2.3_3 Nedbal custom converted Richards I using Uberti Colt 1860 Army C&B pistol with 4-screw frame as project gun

$D:\Uberti Colt 1860 Army (R1)\1-P1020627.JPG$

5.10.2.3_4 Nedbal transformed a pair of Uberti factory beefed-up Richards II fitted with 3-screw frames to Richards I

$D:\Uberti Colt 1860 Army R2 #X22885\1-P1070436-001.JPG$

5.10.2.3_5 Uberti factory Richards II conversion with 3-screw frame beefed-up in all three key dimensions

5.10.2.4

Original and Modern Colt 1860 Army Richards-Mason Conversions

No original Colt 1860 Army Richards-Mason conversion was available anywhere through the FROCS community for measuring. Hence, we had to go back to the McDowell data. It did not provide readings on the height of the barrel lug. Although Colt used newly fabricated barrels for their RMs the geometry of the frames was assumingly not altered. Therefore, we assume that the height of the Colt 1860 Army RM barrel lug compares to that of their C&B brothers.

Colt 1860 Richards-Mason Facts & Figures mm/inch	Serial number	Diameter cylinder front	Diameter cylinder rebate	Height Barrel lug
Original*	average	41,20/1.622	39,83/1.568	n.a.
Nedbal Centaure	#6176	42,06/1.655	40,32/1.587	47,50/1.870
Uberti RM	#X02711	42,44/1.671	41,04/1.616	48,40/1.905

* Measurements from McDowell

Here are the findings:

The forward areas of the conversion cylinders of both the custom converted Centaure and Uberti factory Richards-Mason were found beefed-up although the Centaure came out a mite less.
The Centaure is OK in the other two measurements whereas the Uberti is beefed up in all 3 departments as already found in their Richards Transitional Model!

Go figure.

$D:\FAUL Conversions\1-P1010394.JPG$

5.10.2.4_1 Two Colt 1860 Army Richards-Mason conversions with 3-screw frames (from top): Uberti factory conversion #X02711, Nedbal Centaure custom conversion #6176

5.10.3

Caveat Regarding Modern Colt 1860 Army Breechloading Conversions

According to the research of the late R. Bruce McDowell there are a few other important findings to be considered when you are looking for a modern, dimensional and technically correct conversion.

Colt 1860 Armies with 8” barrels, 3-screw frames and rebated cylinders only were subject to factory conversions.
No factory converted short barrelled, 4-screw frame or fluted cylinder Armies are known to exist.

5.10.4

Conclusions

So, what is all this measuring and comparing telling us? These are my subjective conclusions (you were warned about my subjectivity):

According to our sample the majority of 19th century Colt 1860 Armies has been built with close production tolerances.
Contrary to opinions voiced elsewhere this applies to their modern clones and re-issues as well.
If the objective of your conversion project is historical or dimensional correctness rather, of a safe, reliable shooting iron the quality of the steel used for the making of both the project gun and newly manufactured conversion barrel/liner and cylinder will be a key issue.
Centaures are made of harder steel than Italian percussion revolvers.
Historically and dimensionally correct conversion pistols are available custom made only, not off the rack!
This page helps to rationalize my prejudices and preferences. Vis-à-vis the best wifey of them all it sometimes helps getting subject financial funds sanctioned for my conversion projects, too!

$D:\FAUL Conversions\1-FIL22489.JPG$

5.10.4_1 Modern Colt 1860 Army revolvers and conversions (top down): Nedbal-Centaure Richards I custom conversion #4079, Uberti RM factory conversion #X02711, 2nd gen. Colt Army #US0858, Uberti Richards II factory conversion #X04444

5.10.5

Yes we can – But do we want?

Some cowboy gun shooters consider the Colt M 1871/72 Open Top (OT) the queen of the Colt conversions. But it is no conversion at all. Because the OTs were designed as breech loaders to begin with. Collectors on the other hand often refer to them as forerunner of the Colt 1873 Single Action Army which is another misconception.

Be that as it may with the experience gathered by now through other Centaure conversion projects it appears the way is paved for the making of a Centaure Open Top (OT) with Army grips in .44 Colt cal. using many original Belgian Centaure parts. Here is a preliminary shopping list and a rough outline of such a project:

# The original Centaure backstrap, grip and small parts can be used.

# The watertable of a Centaure 3-screw frame with typical stepped water table needs to be built-up (!) into one straight platform, see picture of an original Open Top below. The notches of the recoil shield will have to be filled to end up with a round frame, see Nedbal’s Centaure “Mystery” conversion in chapter 5.5.

# The loading gate with external spring will have to be added. Of the existing C&B hammer the rear sight is to be removed and a firing pin added.

# A Uberti made steel triggerguard will be required and mated to the reworked Belgian frame, backstrap and grip.

# Then a straight cartridge cylinder with Open Top gas ring at the front needs to be lathed from ordnance steel. No big deal for a conversion artist.

$D:\Colt 1871-72 Open Top\1-250af82ddfef2377a02033dfc4bbdc38.jpg$

5.10.5_1 Nickel plated original Colt 1871/72 Open Top, ivory grips of Army size, .44 Henry RF cal. (picture courtesy Collectors Firearms, Houston, TX, U.S.A.)

# As for a barrel another semi-finished 7,5” Open Top barrel, this time with a long (!) forcing cone, integrated rear sight and rifling groove diameter of .429″ should be procured from Uberti. It will require adjustment of its height, re-contouring of the „S“ curve of the barrel lug and fitting to the Centaure frame, see Richards-Mason project in chapter 5.4.

# An OT late type wedge of Uberti without spring might be saving some gunsmith time.

# A new ejector housing will have to be milled and mated to barrel, see also RM project in chapter 5.4.

Such a Centaure Open Top will have even more Italian genes than the previous Centaure Richards-Mason conversion project. Will I pursue such a project, the War Department permitting? Unlikely, let me explain:

„Technically and compared to a Thuer or Richards for example the alteration of a Centaure percussion revolver into an Open Top is an unsophisticated piece of solid gunsmith work, but a demanding task, nonetheless. It might represent some unexpected challenges.“

„An experienced, dedicated and top-notch conversion artist is required to execute such a project. In Europe I only would trust Karl Nedbal with this task.“

„With due respect to my friends in Gardone and Messkirch I am the happy owner of a couple of Long Cylinder Conversions (LCCs) built from Centaures. These LCCs share key characteristics with the Open Top. From a technical point of view, they are the predecessors of the OTs, see chapter 5.7 for details.“

„When it comes to considering another modern, hard steel and quality made Colt 1860 Army conversion with proper dimensions and contours with the options available today I will be choosing a Centaure customs conversion in .44 Colt cal. every day of the week over such an Open Top.“

$D:\FAUL Conversions\1-P1070480.JPG$

5.10.5_2 Nedbal custom Centaure Conversions proudly displayed on the Austrian State flag (top down): Thuer #7266, Richards (R1) #4079, Richards Transitional (R2) #6981, Richards-Mason #6176, “Mystery” #11691, Long Cylinder Overland Stage L. 2 #13859

„I am bowing my head in great respect to the outstanding work of Austrian master Karl Nedbal, as exemplified by the above quintet of full size Centaure Army conversions you built for me.“

„Thank you, Karl my friend, you have been doing good!“

Updated February 20, 2024

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