From FM 31-70 APPENDIX D
During the winter, weapons must be stripped completely and cleaned with a drycleaning solvent to remove all lubricants and rust prevention compounds. The prescribed application of lubrication oil, weapons (LAW or Lubricant, Semi-Fluid, MIL-L-46000(LSA)) should then be made. These lubricants will provide proper lubrication during the winter and help minimize snow and ice from freezing on the weapons.
