Secretly buffed in the Season 5, the R9-0 was given an explosive modification. The little-used shotgun was given an ammo modification called the Dragon's Breath rounds.
Here is why you should start using this shotgun and add it to your Call of Duty: Warzone and Modern Warfare rotation.
Warzone R9-0 Dragon's Breath: How to Unlock
The Dragon's Breath rounds add a new factor to the close ranged gun. Instead of firing out regular shotgun shells, the shells are on fire. Not only will an opposing player take damage from the shell but they will also continually take damage from the fire. This makes the gun an even bigger threat in close range.
In order to unlock the ammo modification, players must get 10 kills while sliding. The opposing player must be killed not just downed so make sure after sliding in, you secure the kill. This mission can be fulfilled in any way that a player wants. It will be faster to get the modification in Modern Warfare due to the pace of the games while it may take longer in Warzone.
The R9-0 Dragon's Breath rounds are overpowered right now and will most likely be nerfed in the near future. Whether it is noted in official patch notes, or secretly added to the game, it is best to take advantage of the weapon for as long as possible due to its massive damage output.