Each rifles start with a 100% Weapon Bonus. By upgrading the rifle, this Weapon Bonus increase. This is also reflected in the Result screen at the end of a mission, where the additional Weapon Bonus obtained is displayed at the very end of the list.

Once a rifle is fully upgraded, players can start Mastering the rifle. Each Mastery Level boost the Weapon Bonus even more. Once fully mastered, an overall Weapon Bonus is applied to all rifles. Players can see the maximum Weapon Bonus next to your actual Weapon Bonus. Once all rifles in the game are fully Mastered, each rifles will have their maximum Weapon Bonus reached.