5.5 The Infamous Centaure Mystery Conversion

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

5.5 The Making of the Infamous Centaure „Mystery“ Army Conversion
















The Making of the Infamous Centaure „Mystery“ Army Conversion

What is a Colt „Mystery“ Army Conversion?

The Making of the Nedbal Centaure „Mystery“ Conversion

Progress Report


1st Annual Meeting of the FROCS in 2010 and Other Little Details

More Centaure „Mystery“ Conversions?



What is a Colt „Mystery“ Army Conversion


Who needs a newly made Colt 1860 conversion cross fitted with an army barrel with cool looking barrel lug of 1861 Navy conversion contour, on which a Richards-Mason type ejector housing is mounted with dimensions differing significantly from the typical RM Armies assembled in Hartford during the 1870s, and a RM cylinder and frame assembly with a narrow saddle-type conversion ring fitted for good measure?


D:\Colt 1860 Army Mystery Conversion\1-FIL22505.JPG

5.5.1_1 Colt 1860 Army “Mystery“ Conversion as discovered in R. Bruce McDowell’s conversion bible, typical Mexican style engraving, nickel plating, sculpted ivory grip


Even though some of the collectors call these „Mysteries“ Colt 1861 Richards-Navy conversions on steroids, every red-blooded cowboy or cowgirl should have one or better still a pair. Because less than a dozen only from yesteryear are known, probably made south of the border in Mexico around 1875. At least that is the considered opinion of the late R. Bruce McDowell in his famous conversion bible A STUDY OF COLT CONVERSIONS AND OTHER PERCUSSION REVOLVERS. Original “Mysteries” were made for the venerable .44 Colt center fire cartridge!



The Making of the Nedbal Centaure „Mystery“ Conversion


When Karl Nedbal phoned on December 31, 2008 with an update on the Centaure Richards-Mason we agreed that a „Mystery“ was going to be the next conversion project. Designated candidate for this somewhat exotic conversion was to be my 1971 production Regular New Model Army (RNMA) 1st variation 2nd sub-variation #11691. The project was formally kicked-off on April 30, 2009, the day the Richards-Mason came home.


D:\FAUL RNMA 1V 2SV #11691 Nedbal Mystery Conversion\1-FIL11955.JPG

5.5.2_1 Project gun for the „Mystery“ Conversion: Centaure RNMA 1st variation 2nd sub-variation #11691



Project Outline

Project revolver

RNMA 1st variation 2nd sub-variation #11691


8″, barrel lug with Colt 1861 Navy conversion contour

Barrel marking



.44 Colt inside lubed (liner, .429″ rifling groove diameter)

Ejector housing

Richards-Mason type


altered to Civilian type round frame



Conversion ring

gated, Richards III type

Conversion cylinder

newly lathed conversion type, Centaure proprietary naval scene custom engraved


altered C&B type from Centaure

Gate spring


Grip frame

Centaure brass triggerguard, backstrap with with notch


traditional (rust blued, case color hardened)

Progess Report


It was agreed that Karl would not dash ahead at his usual pace of three months for the completion of a Centaure conversion but take his time with the „Mystery“ project. So, he researched what little he could find to read about the “Mysteries”. In fall of 2009 he started working metal. Here is what we have on November 9, 2009, see pictures below. Nedbal had

# Reshaped the 1960 Army’s percussion barrel lug like one of a Colt 1861 Navy Richards-Mason conversion,


D:\Colt 2nd Gen. 1861 Navy RM-Conversion #40660\1-P1040687.JPG Next of kin: 2nd gen. Colt 1861 Navy Richards-Mason Conversion #40660 .38 Long Colt cal., 6″ barrel


# Plugged the slot for the loading lever in the barrel lug,

# Installed the Richards-Mason type ejector housing.


D:\FAUL RNMA 1V 2SV #11691 Nedbal Mystery Conversion\1-FIL10867.JPG Reshaping Centaure barrel lug to Colt 1861 Navy RM conversion contour, ejector housing installed


# The S-line on both sides of the barrel lug is now more pronounced in true 1860 Colt-fashion. This operation did not harm the Liège proof house stamps.

# Karl removed the Centaure step where frame and barrel lug meet.

# For the “Mystery” Nedbal left the Belgian factory arbor in place but

# Opened-up wide the right side of the recoil shield. This way room was made for the internal spring-loaded gate of general RM Navy 1861 outline, just a mite larger.


D:\Colt 2nd Gen. 1861 Navy RM-Conversion #40660\1-P1040689-001.JPG Right side view of Colt 1861 Navy RM conversion #40660


# For a period-correct installation of the Richards III type conversion ring of saddle design master Nedbal will have to attach it to the recoil shield by a screw. This required working on the two notches for the shoulder stock and welding them shut. He then contoured and finished that area to shape. This way the frame has no longer has the typical RNMA contour with two notches.

# This little operation transformed the frame of #11691 it into a round Civilian contoured frame. Neat little job, isn’t it?


D:\FAUL RNMA 1V 2SV #11691 Nedbal Mystery Conversion\1-FIL13436.JPG Nedbal magic: Transforms RNMA frame into round Civilian-type frame for the „Mystery „project


# Regarding the finish of the Centaure „Mystery“ conversion we have a change of the original plan. Most of the „Mysteries“ documented were nickel plated. But after my shooting experience with the Centaure Richards-Mason it is going to be Nedbal’s traditional rust blue. He will make every effort to maintain as much as possible of the pretty factory case colors of the frame.

# November 14, 2009: The loading gate is shaped and installed.