And that gun looks to be a very nicely drawn M9 (Beretta 92F) sidearm, so it's presumably his service sidearm from before his death and resurrection.
Of course, you're not gonna hit the broad side of a barn with a 9mm beyond about 20 yards, so I'd halfway expect him to keep an M4 carbine (shortened M16, basically) on his back for long-range work, but Foxhack's points still stand.