if we go with the giving carbines to engi idea lemme suggest a few

1. HK-51: 3 tap kill at close range with 700 rpm and high recoil and a maximum mag size of 25
2. Sr3m: 28 dmg at 950 rpm with somewhat assault rifle like accuracy and moderate recoil
3. Scar-16 carbine: 25 dmg at 650 rpm low recoil with decent accuracy (comparable to lmg)
4. .50 beowolf smg: low capacity low accuracy very high recoil and high dmg I feel like this gun speaks for its self
5. mcx rattler: reliable close to mid range option