From the Mk23 wiki
The requirement was for no less than 2,000 MRBF; the HK OHWS averaged 6,027 MRBF and could reach 15,122 MRBF. Three pistols went through a 30,000-round endurance test and maintained accuracy of 2.5 in (64 mm) at 25 meters; only the O-ring needed replacement after 20,000 rounds.