6.2 CAS-Tuning

Chapter 6 – Centaures the Glorious Shooting Irons and then Some

6.2 Cowboy Action Shooting – Need for Some Tuning























Cowboy Action Shooting – Need for Some Tuning

(by Michael „Socks“ Mayer, translation Jörg „Magic Joe“ Ullrich)


Hammer Stop

Centric Alignment of the Hammer


How To Prevent Caps from Popping Off the Nipples

Polishing the Sliding Surfaces

Adjusting the Timing

Iron Sights

Thoughts about Tuning






The main spring or hammer spring can be replaced by a weaker one or ground down. When opting for grinding this is a delicate job. You need to work very careful to reach a smooth and even surface of the spring. A thorough polishing is highly recommended. Every weak spot, scratch or unpolished file mark is a potential breaking point!



6.2.1_1 Thin aftermarket hammer spring


The original cylinder stop/trigger spring is a leaf spring and quite prone to breaking. This usually happens in the middle of a match. It should be replaced by one of the almost unbreakable piano wire trigger/bolt springs.


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6.2.1_2 Aftermarket piano wire trigger/bolt spring instead of the original, fragile leaf spring



6.2.1_3 Cylinder stop/trigger spring – replacement piano wire spring installed


Another leaf spring is responsible to working the cylinder rotation. This spring of the so-called hand is another candidate for breaking. It can be removed and replaced by a coil spring with a transfer bolt, after drilling a hole into the frame’s back side (see pictures below). The screwed-on backstrap keeps coil spring and bolt in place and provides the necessary spring tension.


Please take notice:

In many European countries this procedure of drilling a hole into the frame has to be executed by a certified gunsmith and might require a new proof testing.



6.2.1_4 Cylinder’s hand with leaf spring pulled; to the left transfer bolt with coil spring



6.2.1_5 Close-up of coil spring, bolt, modified hand



6.2.1_6 Frame with additional drilling hole above the left frame screw thread



Hammer Stop


A hammer stop can be installed. It serves to limit the hammer’s movement down to the necessary distance only. This will reduce unnecessary wear of other moving parts. For the installation of a hammer stop you must cut a thread into the trigger guard from the top and fit a screw into place. The hammer’s travel way then can be limited by screwing in or grinding off the screw which directly affects the hammer spring resting on top (see pictures).



6.2.2_1 Screw fit into the trigger guard


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6.2.2_2 Hammer stop – mode of operation



Centric Alignment of the Hammer


Aligned correctly, the screwed-in hammer should fall into a snug fit in the frame driven by just its own gravity. Some Centaures present themselves with too much clearance between the hammer and the frame. This causes the hammer to move slightly to the left or right dragging along the inside of the frame. This dragging in turn will slow down the hammer and might cause failures to ignite the caps.



6.2.3_1 Such thin washers will secure the centric alignment of the hammer


This situation is eliminated by fitting thin washers on the hammer screw. They ensure the hammer’s centric alignment.





The cones of the original nipples installed at the Belgian factory are of almost cylindrical shape. This shape might cause the caps to slide off the cones. To overcome this situation exact measurements of the distance between the nipples and the hammer’s striking surface were taken. Then the factory nipples were replaced by new ones, specially produced according to these parameters from beryllium copper.

Those beryllium nipples have a thread measurement of .225 x 32G.