Ammunition made with bullets composed entirely of copper ( Barnes Bullets)
These combine the best features of both soft point and polymer tipped bullets, the bullets are formed very specifically to expand with "petals" that cut a massive wound channel that facilitates bloodloss. They also have polymer tipped (tipped tsx) that aid in both penetration and long range stability. Of course the downside is price, double the polymer bullet loads in the same caliber
E.G. polymer bullets for the .243 will cost you 530 credits, copper bullets would cost 1060 credits.
Older rifles like the .270 could benefit from a stronger ammo and it could add a new functionality to weapon XP which is not used to unlock weapons anymore and currently has no use besides a sort of pay wall for new players