I had more than 1 million experience gained with my XT railgun, and with the changes to the skin XT zerou the whole experience
As the XT update converted the XT weapons to actual skins it will only count the amount of experience you had earned with the Normal Version of Railgun.
As The New XT Update Come. The XT Weapons is Now Only a Skin of the Railgun. The Experience Gained Through Railgun or RailgunXT is Under One Head i.e. Railgun.
Customer support service by UserEcho