i would check the gas key on top of the carrier. i would also check out the bolt extractor-gas rings ect. any of your current mags have anti-tilt followers?? i say that because the short followers can tilt over and cause all kinds of weird jams. what ammo are you running in it? what mags?
and lastly make sure your mag is fully seated--you would be shocked how many folks that don't have their mag all the way seated and can't figure out the problem. on the training range i yelled at the boots--slap it in HARD!
i have several AR-15 and fired the m16 m4 series for several decades in the service i can't say i ever saw ONE that had to run sopping wet with oil. such an animal could exist but so could big-foot!
in dusty desert areas we were very minimal with the oil as it attracts dust. it needs some oil but that sopping wet oil deal is a bit much. i did qualify once with a bone dry m-16 firing a full automatic rifle course. did the whole day without a hiccup. flooding the weapon with oil certainly shouldn't be needed.