A debris barrier snap fits to a tubular groove of one of the tubulars that define the annular gap in which the barrier is to be mounted. It is loosely mounted so that it can center itself in the annulus as the relatively moving members go out of a concentric arrangement. The continuous carbon fiber material used for the debris barrier has lubricious qualities to act as a bushing when the annulus shape changes due to movement of the tubulars out of a concentric relationship. An outer or inner groove on the barrier acts to trap and retain small particles that manage to advance between the barrier and the outer tubular. The snap fit is accomplished with flexible spaced apart fingers with grip surfaces to engage a groove on one of the tubulars. The barrier has low expansion under thermal loads that acts to stop the entrance of debris.