split/line through my model?

11415-barrel2.jpg

I cannot work out if this is a lighting issue or not, but I’ve gone through all the import options for the model, and I can’t seem to fix it. Changing the ‘hard angle’ does seem to change something, but makes the model look worse and weird.
I found that the Lightmapping Resolution does not match up along that line.
Any ideas on how I can fix this?

On the Object inspector set the Normals to Calculate then set the smoothing angle to somewhere below 60.