The first laboratory slide failure, which occurred on February 8, 1988, involved an Army M9 firing NAKI standard U.S.-produced M882 ammunition. This weapon was one of three M9 handguns being tested for problems related to the barrel. As part of the test, all three weapons had been inspected after 6,000 rounds using a scanning election microscope (SEM) or magnetic particle inspection (MPI) process, and there were no indications of slide cracks. When the M9 slide failure occurred at 6,007 rounds, the broken slide and the slides on the other two test weapons were removed for metallurgical evaluation. The evaluation showed that one of the other slides also had fatigue cracks. This evaluation marked the beginning of an Army slide failure test program to determine why the failures had occurred.
The Army replaced the slides on the three weapons and continued to fire the M9s, using NATO standard ammunition, until each broke. One slide failed at 4,908 rounds, another failed at 21,942 rounds, and the third failed at 21.486 rounds.
The next grouping test results for four other weapons: one M9 and three Army-owned commercial (92SBF) handguns. The slide on the M9 failed after 7,806 rounds, and the slides on the three 92SBFs failed at 17,408, 21,264, and 24,656 rounds.
In 1985, the Army acquired three commercial 92SBFs for testing to determine which part would fail first. The first part to fail was a barrel. After the barrel failed, the Army suspended testing and inspected the weapons using an WI process. The inspection showed slide cracks on all three weapons. Because slides are considered spare parts and there had not been any slide failures at that point in time, the cracked slides did not raise any specific concerns.
The final grouping of weapons involved three M9s that were being tested as part of an annual comparison test. After the weapons were fired 10,000 rounds, the slides were inspected using the MPI process and one slide was cracked. The Army decided to fire all three weapons until the slides failed. Slide failure occurred at the 23,310 round mark on one weapon, 30,083 on another weapon, and 30,545 on the third weapon.