Copper bar, oxygen free, tem h; o/a lg 0.814 in.; first shoulder diameter 0.270-0.280 in, 0.188 in. Lg; undercut 0.125 in. Dia, 0.188 in. Lg; second shoulder 0.270-0.280 in. Dia, 0.188 in. Lg; undercut 0.062 in. Lg, 0.080 in. Dia; threaded 0.188 in., 0.112-40 unc-2a