At MG shoots we'd try all these products looking at number rounds till it starts to choke. Depending on ambient temps grease (ie., heavy on the wax) is a perfectly good way to go for AR15 upper components. Rotella held up longer than 0W-20 motor oil, which held up longer than ATF, which held up alot longer than CLP.
Some days could not even get through a 100 bird clay shoot after lubing a 391 with CLP.
