Aeroshell 64 grease which is the equivalent of the discontinued Areoshell 33MS is designed to prevent the threads on your Modern Sporting Rifles barrel nut from locking up. Aeroshell 64 is an extreme pressure grease that is specially designed to prevent galling. If this grease is used on your build you will be able to easily assemble and disassemble your rifle without the possibility of thread binding. Normal grease and oil will be squeezed out when tightening the barrel nut causing the metal parts to touch each other. This increases the risk of damaging the threads and can cause the threads to bind. In addition Areoshell 64 can be used for any high heat and/or pressure application in which you do not want threaded parts to gall or bind together.