Fe‐Co and Fe‐V alloys, tested in static ultrahigh pressure apparatus, have been found to have resistance jumps resulting from the &agr; to &egr; transformation, as in pure Fe. The pressure of initiation of the transformation increases with the alloy content; from 131 kbar for pure Fe up to 290 kbar for 20 wt% Co. The V alloys rise much faster: 280 kbar at 6 wt%. The Fe‐Co alloys can serve as convenient samples to pressure‐calibrate apparatus in the 160 to 300‐kbar region. The difference between the pressures of initiation of transformation under static conditions, compared to shock conditions, is zero for pure Fe and progressively greater as the alloy content increases.