The Rifle Bullet attachment is exclusive to the M30 Luftwaffe Drilling in Call of Duty: WWII. It allows the player to use the third rifle barrel of the M30 Luftwaffe Drilling. Incendiary Shells cannot be used in conjunction with this attachment as they both take up the same activation button.
Pressing the 'Left' button on the D-Pad (Xbox One and PlayStation 4) will switch to the rifle bullet and will bring up an iron sight which can be used to acquire targets easier at ranges.
Damage-wise, the rifle bullet has similar damage to the Lee-Enfield, requiring a shot at the upper torso or above to kill. In hardcode, it is always a one shot kill, regardless of where the bullet hits. Also, the rifle bullet, unlike the regular shells of the M30 Luftwaffe Drilling, have significantly higher range, being able to reach enemies from further distances. Using the rifle bullet at close ranges is not recommended as damage is somewhat inconsistent.
Using this attachment with the Reflex Sight can make the M30 into a pseudo-sniper , due to the Reflex providing better target acquisition at range.
Previously, switching back to the regular shells of the M30 Luftwaffe Drilling from the rifle bullet had no delay, meaning that a user could instantly fire a shot from the regular shells if the rifle bullet misses or a second close range target appears. This has since been patched, requiring the player to perform an animation of switching to the shotgun shells.
With the divisions overhaul, using the rifle bullet now grants 8 bullets instead of 6, to bring it on par with the incendiary shells buffed in the same update.