Chance one’s arm
Take a chance or take a calculated risk, this British expression dates from the late 19th century and there are at least three theories about its origin. Firstly, some etymologists maintain the origin is from tailoring, although the link to tailoring is somewhat obscure. Secondly, it is thought to be derived from the military i.e. chancing the loss of the stripes on one’s arm. And finally, some say it comes from boxing, in delivering a telling punch. Chance your arm and take your pick because no one knows for sure.