This is a problem on my Les Paul (deluxe, 1972 if it matters). As I often get a pretty mixed set of string gauges, I often buy my high two strings as "loose", and haven't paid close attention to to the brand. I guess I was thinking all plain steel strings were basically the same, as long as I stick with some name brand. But I had bought a dozen each 0.009 and 0.0115 D'Addario strings (mainly because they have a hard to find 0.0115 I use for a "B" string).

So the problem is, more often then not, I'll notice that on every bend of the high E, it will be flat afterward. Its not unwinding at the peg, and I don't have a sticking problem at the nut. What is happening is the string slightly unwinds from its little brass ring at the tailpiece. (The part Gibson also calls a "stop bar"). Eventually the string will break during a bend, but on close inspection it has just unwound, and sure enough there will be a little brass end ring somewhere on the floor.

I can't imagine any kind of defect in the tailpiece. But this is happening too often. Anyone else have a similar problem, and if I'm going to buy loose plain steel strings, which brands are less likely to have a problem like this? I have a feeling that D-Addario strings are not a brand commonly used for rock playing, so those were probably a bad choice.