Yeah, actually you do - corrosive salts from the priming compound used in this ammunition will cause rust and corrosion to form under the oil. Water (as hot as humanly possible) dissolves the salts, oil simply encapsulates the salts and holds them against the metal.
OP - did this happen with one mag, or all mags - you might have some mag lips that need tweaking.
Wait a minute! You're saying that AFTER being cleaned, the rifle will continue to corrode? I could see it happening if he just oiled it after shooting corrosive, but not after cleaning.


















































