Can a science geek please explain what's with all the flame billowing out, and the exploding target? My expertise in railguns is from Battle/Quake so I wonder what is with the incendiary aspect?
Having read about it a bit, I'm pretty sure that's the sabot disintegrating. The actual projectile is encased in a discardable mold to hold it in the right place within the loading chamber. This ensures that it is in the right position for the magnetic field to catch it.
Upon launch it reaches such high speeds so fast that inertia, and drag from the air disintegrate the sabot leaving the projectile to hit the target alone. (Which is good because the sabot is usually a big soft thing that would lower the ration of kinetic energy delivered over time if it also hit the target.) I'm guessing this thing moves so fast in fact that the sabot is combusting in air.