The Bureau of Mines, U.S. Department of the Interior, has used a shock accelerometer to measure deceleration in ball-on-ball impact. The accelerometer signal was analyzed by a fast-Fourier-transform (FFT) technique, and signal components were identified from the accelerometer characteristics, solid mechanics, and finite-element modal and spectral analysis. Following frequency-domain digital filtering to remove extraneous frequencies, the remaining signal was reconstituted by an inverse FFT. Supporting Hertzian quasistatic and elastic and elastic-plastic dynamic finite-element calculations were carried out. All calculations predicted similar peak decelerations and contact times. The former agreed well with experiment. However, stress-wave effects make it difficult to use deceleration measurements to define contact times, even at an impact velocity of 8 ms−1. Such an impact must be analyzed as dynamic rather than static.