After broach rifling, the button rifling method was developed. This was a radical departure from both cut rifling and broach rifling in that rather than cutting the grooves into the barrel, they were pressed into the barrel. This tool employed is made from solid carbide, is larger than the reamed bore, and is either pulled or pushed through the bore, depending upon the type of machinery used. Any toolmarks that are in the barrel before rifling with the button will still be in the barrel after the rifling, although they will be smoothed considerably. When the carbide button was first introduced it was described as a swaging process or swaged rifling. Refer to Button. The image below is of a button. Photographs courtesy of Scott Doyle –http:// www.firearmsid.com
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