Bridge problem.

It's possible that there is a burr on the saddle barrel.Is it always the same string?That is usually the case. Do you have your strings tuned to standard tuning(440 Hz).Do you change your tunings?If you can answer these questions I can supply you with an exact fix.If it is one saddle that is the offending culprit, and if it is not a plated saddle,as in gold or gold color, chrome or some other plating you can probably feel the burr.You can very carefully use a small bit of 800 grit metal oxide sandpaper to rid your sadlle of the burr,or a very cool trick that works quite well, is to replace your strings and after you have fed them thru' the body of the guitar slip a short piece of wire insulation on the string.You will have to use different gauges of the insulation, from about 10 to 16. Look and see what sizes work best for the gauge of strings you use. You strip a piece of the wire and harvest the hollow piece that you stripped. This piece will be slipped onto the string and as you set your string place the insulated part of the string directly on the saddle.I suggest that you invest in some graphite saddles.