Using a TLD for BlogSpot Blog

I want to use a TLD for one of my Blogspot blogs. But i have no idea what will happen to my current traffic flow and posts listed in search engine result pages.

Since we can't use 301 redirect manually I wonder if Blogger do it automatically or The blog will loose all its traffic and rankings.

I think you will loose your all traffic if can't use the 301 redirect

Blogger has been out there for an very long time. So I hope they have some kind of solution for this. There must be a way !