Nato ammo is known to work well with the 16 inch and up though. Maybe a 10.5 inch for pilots. The infantry uses SCAR Hs, Because I like .308
I have 2 more factions to do:
Mercenary Company:
Mercs hired to take out resistance, bad guys, use some nice stuff
Thugs:
A gang trying to take down resistance for bounty on them, uses street junk, like lorcin/raven 25s some 380s maybe an occasional glock and higher ranking ones use status symbols like the tec 9 and tehir bosses may have a stryker, ak, etc.
Im thinking the resistance can find a cache of class 3 weapons, like an m16a1, colt 9mm smg, fn fnc, steyr aug, sterling smg, stechkin aps, just a random assortment