This is a small suggestion to add a semi-automatic rifle for the Security side to potentially increase the balancing between each faction's weaponry.
Whatever the 7.62 Semi-Auto Rifle should be, should be a available for Rifleman, Advisor, and Marksman.
If adding a 7.62 Semi-Auto Rifle is determined ahead of time, then disregard this post's suggestion.
I have some ideas for a powerful Semi-Auto Rifle if adding one isn't planned ahead (all of them loaded with 20 rounds):
L1A1 (From INS)
M14 (Classic Rifle)
SR-25 (One of US Armed Forces' standard Marksman Rifle)
L-129A1 (One of British Armed Forces' standard Marksman Rifle)
RFB (Based off of Brightside's popular Mod that replaces INS's M39 EBR)
SCAR-SSR (Generally a Marksman Rifle Version of SCAR-H)