I just very recently got the Paul Reed Smith SE single cut in tobacco sunburst with the tremolo. A while back I contacted PRS to see what options I had for locking tuners and they told me that Grover 406c locking tuners would be a direct replacement. Really never used locking tuners in the 12 years that I've been playing. I looked at a YouTube video to make sure I was stringing them right and I'm assuming that I am. I stick part of the string in the post and turn it till the tuners lock the string in and then finish tightening the string. I tried to let the string go around the post once or twice, though the instructions that came with it or to my knowledge that is not required. Issues: 1. I can turn some of the tuners just a little bit and get a decent distance on the tuning, but on other tuners I have to turn them much further. 2. When I get a string in tune, some of them somehow TIGHTEN (goes sharp) by the time I get back around to check the strings and make sure they are all still dead on (or it goes flat). They go sharp by almost an entire step sometimes in just a matter of 20 seconds. It's just really frustrating and right now they locking tuners aren't doing their job. I thought maybe the trem was off center or something, but I've really no clue what would cause all of this. OH by the way. I know the tuners are labeled somehow, but honestly I'm not sure at all if one tuner is supposed to be for a specific string or not. Obviously 3 go on one side only, but that's about as much as I could tell, because there were no instructions to say which tuner went to which string.