railgun rail erosion problem solved?

[Mauser 98K]

i was thinking the other day about what i read on a popular science magazine, about the future naval ship and the weapons it would have if they worked all the bugs out, and it hit me about the railgun.
a railgun is a weapon that uses an electromagnetic force to accelerate a projectile down 2 rails used as the contacts and to create the magnetic feild required to accelerate the projectile at many times the speed of sound.
anyway they have been trying to figure out how to prevent rail erosion due to the high current (9000J+)used to create the EMF(ElectroMagneticForce)that propels the projectile, and the projectile trying to weld itself to the rails.
they have experimented with diffrent types of metal to use as the rails and as the projectile but as far as i have heard they still got the same problem.

anyway i was having some tooth pain from a crappy wisdome tooth when it hit me, how does a electric motor prevent the erosion of the comutator it has brushes that ride on it, and was wondering, what if a cup made out of the same material was pushed up over the part of the projectile that rode on the rails?
hmmm, it would cirtainly create the connection required to make the EMF and wouldnt try to weld itself to the rails, is in large abundance and is reletivly in-expencive.

it would be cool if it did work