Use a turret on a map with plenty of enemies. By doing this, you will have a longer vision range, do more damage, and allow the turret to take damage instead of you. You have to shoot quickly and accurately to keep the killstreak incrementing to get the medals. Make sure the turret does not overheat to prevent being locked out from using it. You can also purchase a score booster at the start of the map. Note: This can also be done with vehicles.