I have a new Bushmaster M-4 type carbine. I have only fired about 200 rounds through the gun, all Federal or WInchester Ammo. I always thoroughly clean and lubricate the gun after use. Today while cleaning I noticed I have heavy rust in the area of the barrel and barrel extension. Any body else have this? My guns are kept ina safe with a goldon rod and the room the safes in is not damp or moist. Im baffled at why this gun is rusting, none of my other AR's are doing this.