The 4506 I have "under the pillow" is of course, stainless. It gets a periodic cleaning but I think the grease for the rails and locking lugs are better than the oil I currently use. Somewhere around I have some Gun Butter grease but have yet to locate it. Time to just bop over to the gun shop and pick up some sort of grease as many have been recommended here...probably doesn't matter which brand.