x-axis ticks and labels

I am trying to relabel the x-axis on a plot. I want it to have 10 evenly spaced labels ranging from 274 at zero to 283 at one increment short of the axis. My code is as follows:


My understanding is that MaxNLocator defines the number of spaces between labels. I've tried a few variations on the above but can only seem to get the last label to be 282 or 284. Anyone know what I am doing wrong.