I was cleaning my usak getting ready to go to the range on sat. and saw the tell tail sign of rust on my patches, ran 4 patches with rust duck, 4 dry and I don't if I should did it a patch of bore butter (I mainly use rem oil). shined a pin light down the berral and saw some pitting. I only paid $40 for the gun, and I need to last me 2 maybe 3 season. any ideas?