If you are intercepting a 300° magnetic course outbound from a NAVAID, what should you do?

When you are intercepting a 300° magnetic course outbound from a NAVAID, maintaining your present heading is the correct action to take. This is due to the fact that if you're already aligned with a magnetic course of 300°, which typically means that you are on course, turning at this point would actually take you off the desired flight path.

In scenarios of intercepting or tracking a magnetic course, it's crucial to understand that when your aircraft is on the assigned track, maintaining that heading allows you to stay as close as possible to the intended route, ensuring that you follow the course accurately. Any deviations such as turning left, right, or towards any other heading would not be appropriate unless you are specifically instructed to change your course, which is not indicated in this situation.

So, by opting to maintain your present heading, you are effectively flying directly on the 300° course as intended.