Hello, I noticed a bugg in the Last Bullet Augmentation.
The Augment is unlocked when killing the Vulture.
But I tested over the last few days and noticed
that when killing the Vulture with DLC Weapons the Progress of the Aug isnt increasing.
(This also counts in Turrets)
When using the non DLC Weapons it is progressing.
(The new EXP Weapon also increases Progress but not always 
)
Im playing on Xbox one
Played in solo. In MP it crashed most of the times so I stopped trying.
I would like someone else to
also try to confirm it isnt just my Game that has this Issue.
, the best thing to do is to make sure you destroyed the machine with a weapon you know that works 
at least the final bullet, with all that time & effort, just be careful