Give Engineers (replace RPG) and Recon High Caliber armor piercing Rifles (50cal)
Give them ability to break holes in walls, which would be similar to pickaxe
Give them ability to immobilize vehicles (destroy engine, break tire or track from couple shots )
Give them ability to chop threes
Give them stock bi-pod and crazy recoil when shooting without bi-pod being deployed
Keep low ammo, 15-20 bullets