Looks to be improving.
"The US Army selected SIG Sauer’s Modular Handgun System entry back in 2017 and since then the full-size sidearm has begun to reach active units. Some controversy regarding reliability initially surrounded the XM17 but a recent report from the Director of Operational Testing and Evaluation confirms these issues have now been addressed.
The recently published annual report from the Director of Operational Testing and Evaluation (DOT&E) Annual Report confirms the M17 and M18’s reliability performance. The report notes that “the MHS experienced a large number of stoppages in early developmental testing with ball ammunition”, however, it seems this issue has now been addressed by a team of both government and SIG Sauer personnel. To ensure reliable feeding with both the Army’s new 147 grain XM1153 jacketed hollow point round and 115 grain XM1152 ball ammunition a number of changes were made to the magazine spring, magazine follower, slide geometry, and some of the pistol’s internal components. The report concludes that “ the XM17 and the XM18 are operationally effective and operationally suitable with jacketed hollow point ammunition. ”
Examining the data provided in the DOT&E report it appears that both pistols have improved function with both types of ammunition but that the XM18 is now superior to the XM17 in terms of reliability with the compact pistol improving more between the first and second product verification tests (PVT). The XM17’s reliability with XM1152 Ball has improved significantly, but its round count before a failure decreased from 7,009 to 6,349. With XM1153 JHP rounds the XM17’s reliability has decreased with the mean number of rounds before a stoppage decreasing from 2,709 to 1,880. Similarly, the mean round count before failure with the JHP round has fallen from 15,501 to 10,321. It should be noted, however, that while performance with JHP has decreased it is still superior to XM1152 Ball and reliability with both ammunition types falls well within the army’s reliability requirements of firing 5,000 rounds before a failure.
SIG Sauer celebrated the DOT&E report and the positive results of recent Lot Acceptance Testing with a press release. During a round of acceptance testing, 12,000 rounds were put through three M18s without a single stoppage. SIG Sauer confirmed that in addition to the endurance test the M18 also “ passed a parts interchange test, met all of the stringent accuracy and dispersion requirements, was tested for firing pin indent and trigger pull measurements to ensure consistency, and conformed to all workmanship standards. ”