Diesel engine oil and shotguns

Mini rant. I went to the range and saw a guy grab a bottle of diesel in the ammo area he was trying to put diesel engine oil in a Mossberg 930. He put a shot in the shotgun then tried to put the oil in the gun and thought he was coating the inside of the barrel. I told him and he gave me a weird look he was serious. Does he not know that most oil comes out of the ground? I told him and he was so shocked.<br><br>Edit: this was a new guy. I showed him how to properly clean the shotgun. He listened. Does anyone think he has a facebook/instagram<br><br>Edit2: I asked him about he thought of diesel oil and he said it’s so good.<br><br>Edit3: I just asked a vet if they think he’s he thinks he’s the real deal and the vet said no. No angle. Just an idiot