I don't use or recommend them. There are some who say if you use only moly coated bullets and nothing else, it's OK. But one of my customers a few years back took his new 6MM-284, which I had fired a few shots through and gotten some very good groups, and put a couple hundred moly Berger bullets through it. It started shooting worse and worse. He never shot any non-coated bullets through it. He brought the gun back and, after checking all the usual stuff, I spent days cleaning all the moly out of the barrel. Once it was clean, it went back to shooting one hole groups again. After a couple of deals like this, I pretty much stay away from moly coated bullets.