Tungsten Dart Barrel

Based on a very theoretical reasoning the long cylindrical tungsten dart barrel could be the best of them because it is the slimmest and allows the tightest grouping. Good for 140s and 180s. But this reasoning doesn't help you when you are not able to handle such a barrel. Selecting the right shape is a matter of personal preference. Choose what feels comfortable for you. This is much more important than an abstract or "academic" reasoning about theoretical advantages or disadvantages of some shapes.

Tungsten dart barrel is covered by knurling or rings for a safe grip on the dart. Again there is a vast selection of different surface shapes, and combinations of them. And there is the possibility of a plain surface (which beginners are usually unhappy with). Again, it can't be said which variations are the best ones. Choose what suits you, what feels good and what you think you can handle.