While the Marines have confirmed they will test the Army's new handgun, the XM17, it seems they are actually eyeing a more compact pistol to send downrange.
“We prefer our pistol be as compact as possible without loss of capability … after all, it's a pistol,” Chief Warrant Officer 5 Christian Wade saidrecently in an interview with Marine Corps Times. “As soon as the U.S. Army is ready to sell them to us, we will begin this program.”
This explains the Corps' interest in the Army's new XM18 pistol, a compact version of the XM17. It seems possible that the Marines will bypass the full-size XM17 duty pistol all together. The Corps has also been testing out the Glock 19M, which Wade hopes will make its way to Marines in Afghanistan. The 2nd Marine Division's top firearms expert posted a video in August comparing the Beretta M9 and Glock 19.