For sidearm I guess an M1911 45 ACP semi-auto handgun would fit him, if with 21st century stuff to upgrade M1911A1 versions could be with underside rail and suppressor like the MEU(SOC) pistol variant.
Vid from Garand Thumb shooting this 106 y/o M1911 that's WAY more advance & much better alternate option than Orthax's trashy deal to make the first firearms such as the The List- https://www.youtube.com/watch?v=j1smiOWim2o
