How do you get the pardon for Meyers to become Sheriff of Prim?
Tried going to Mojave Outpost, not working?

Have you spoken to Major Knight? He'll grant the pardon after you've met the requirements.

Sometimes the dialogue wont show there's a new option when you talk to him about primm, just make sure to click on all the options. I had the same problem when I first did that quest. Is Meyers in primm waiting for you to get back to him about the pardon.