The U.S. Bureau of Mines, in its ongoing effort to combat the wear of mining and mineral processing equipment, has used several types of laboratory wear tests. Investigations into existing pin abrasive wear testing machines resulted in the construction of the Bureau's own pin-on-drum wear testing apparatus, incorporating the best features of the previous designs. Comparisons of pin diameters, loads, and other factors are made between the Bureau of Mines' pin- on-drum test and other pin abrasion tests. The effects of variations in abrasiveness over the drum were essentially eliminated by making corrections based on the wear of a standard pin traveling a parallel path. Reproducibility of wear values on homogeneous alloys was generally within +/- 0.5 pct. Statistical analyses and test procedures are given for heterogeneous alloys. Design parameters for future pin abrasion tests are recommended.