• Sassen Engineering Ltd
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Button Rifling

Our most common form of rifling at Sassen is the buttoning process. It is a cold swaged rifling method where no cutting of the metal actually takes place but it rather irons the grooves into the barrel instead.

We use a Carbide, 2 stage button, coated in titanium nitride (TiN) which is attached to a high tensile Vasco steel rod. This is then pulled through the correct bore size barrel blank using our custom built, twin hydraulic cylinder buttoning machine, giving us 20 metric tons of pulling force. Before each barrel is buttoned, we coat the inside bore with a special lubricant paste that ensures smooth swaging of the metal and increased uniformity of the rifling twist.

After this process the barrel blank is then stress relieved at a certain temperature and set time, using our fully calibrated heat treatment oven. Once this is done, we can move onto the profiling of the barrel blank with the confidence that it will not warp or change bore size as we remove metal.

Each button barrel is then hand lapped to create an ultra-uniform twist and dimension along the whole bore. In return this creates a smooth surface finish on the inside which greatly reduces copper and carbon build up as the firearm is shot and hence greater accuracy over longer periods.

We cater for most common calibres and twists with our extensive stock of in-house buttons, but if you require something unique please feel free to contact us and we can discuss custom tooling options to meet your demands.