Not sure if there is a "factory replacement" available, but I would check an old time country hardware store. We have one near here that I would bet that if the equivalent set screw is available, they either have it or would get it for you. I love going there for small pieces like that. They have the individual pull out drawers, where you can buy one screw at a time. (Matter of fact, I'm heading there tomorrow to get a new screw for the front of a charge bar on a MEC reloader. By the time I'd mail order one from MEC, it would be many times more expensive than at the hardware store.)
