I think erosion may be a significant factor in this equipment.
That is what the spectrographic study was trying to determine, essentially. What is in the plasma and where it that coming from? Some from even the screws used to attach measurement devices near the muzzle. Some from aluminum plugs in the copper, some from the projectile itself. When those temperatures are generated it is going to wear something. The question of whether that affects ballistic properties of the projectile, or how it affects the accuracy of the weapon itself would be raised.
The extremely large guns, from railway guns to the tube type guns Saddam was building, suffer from severe bore erosion, and I think the question was of how bad that would be in a railgun--which would affect its combat utility on any vessel. Still, they might be cheaper than the $800K per round of the Zumwalt class main gun.
