Tungsten Dart Barrels
Compatibility Standards of Tungsten BarrelsCompatibility means that you can for instance attach shafts of one shaft manufacturer to barrels made by a different company.
Steel tip and Soft tip of Tungsten Barrels
"Classic" steel darts have solid attached tips. This means they can't be used for soft tip darts. A classic steel tip dart has the fixed tip on one end and a thread for the flight on the other.
Soft tip darts have threads on both ends. One is for the plastic tip and one for the shaft. You can use these darts for steel if you replace the plastic tips with replacement tips for steel darts. Such replacement tips are available in various shapes.
However, there are steel tip darts that also have two threads. They are usually meant for use with "movable tips". Such tips will reduce bounce-outs. These darts, although intended for steel only, can also be used for soft tip. Just replace the movable tips with soft tips. On the other side, most soft tip darts can be equipped with such movable steel tips. Only "most" because some movable tip systems require a thread deeper than usual. For instance Unicorn's Hammer Head system can be used on normal soft tip darts, while Harrows' Power Point system can't.
Threads of Tungsten Barrels
The threads of all usual tungsten darts are called "2BA" which follows a British norm. Older brass darts often have a 1/4 inch thread. These two threads are not compatible. 1/4 inch threads are as ancient as brass darts are, so there usually is no need to worry about that when buying a tungsten dart. Standard shafts or soft/movable tips you buy are equipped with the 2BA thread, so problems with incompatibility of the threads should not occur.
However, there are some pitfalls. Some dart manufacturers supply darts with "alternative" attachment methods. The GT series of Bottlesen Hammer Heads is such an example. The shaft of this dart isn't attached with a thread, it is attached through just a thin whole and a rubber tube to fix it. This system is unique -- as good or as bad as the thread system, but you have to take into account that for shafts for this system you will have to rely on the manufacturer. For other companies supplying a shaft only for such special series is not economical.
Another company that comes to my mind here is Unicorn. They are using the 2BA thread, but the outside measures of their darts' flight ends are slightly bigger than those from other manufacturers. This means that Unicorn shafts won't give a plain cut between dart and shaft on non-Unicorn darts. The shaft will slightly jut out on any other dart. Of course all other shafts will be slightly thinner than the barrel if attached to a Unicorn dart.
The bottom line is, if you are buying a new dart take your old spare parts with you to see if you can use them on your new dart. If you buy your first dart set, try to attach the cheap standard spare parts of the shop to this dart, not the ones that are shipped with the darts when you open the box.