Two pressure-measuring devices using SR-4 strain gages and steel pins of ⅛ in. and ¼ in. diam, respectively, were inserted in the wall of an extrusion cylinder. During the extrusion of commercially pure lead the mean pressure and radial wall stresses were measured and found to be in close agreement with the calculated values. The calibration of the instruments showed considerable difference between the curves obtained from dead-weight calibration and those found from a simulation of the extrusion process.