I'm using last dagger but it's not giving me any effect from reactor

[Vertutame]

last dagger mouth thing

[Kahvipannu]

You have to wear it (mounting), won't get the bonus with your other guns.

[Vertutame]

Originally posted by Kahvipannu:

You have to wear it (mounting), won't get the bonus with your other guns.

it was underwhelming...

[Rogue]

You need to switch to it to get the bonus, spam skills and switch to your main weapons (If your last dagger is not the main) for firepower.

[Luna]

If you mean visually in the menu, switching the dagger's slot usually solves this. But yeah the bonus only applies if you are holding the weapon unholstered.