I've got an 18" single cut mill bastard that's nearly 2" wide. It's draw-filed about 275 barrels, and I doubt I'll wear it out in my lifetime. It gives a perfect finish for browning, but when I rust blue, I use the same file to back abrasive cloth after drawfiling, so I get a finer finish. I find that any other file that is smaller, fills with steel too quickly, and needs constant attention. By the time I've got to the finish stage on a rifle, I find I have to draw file a barrel anyway - it's too marked up from the building process to pass muster. But I agree that Rayl's barrels, and perhaps to a little lesser extent, Green Mt., are hard to file.