McCoy Tyner: ''Reflections.'' McCoy Tyner, piano, with various groups. Milestone Stereo M-47062. - This latest from Tyner is a retrospective of his recordings with Milestone from 1972 to 1975, and marks, according to the liner notes, a period of ''intense self-exploration,'' wherein Tyner would develop his own musical voice. This was a period in which percussion became very important to Tyner, and he added two percussionists in addition to his regular drummer on some of these dates. Overall, the music is intensely passionate, with the two hands working together, each seeming to try to dominate the other. Tyner was at work creating a system that would influence a whole generation of young pianists. The Milestone groups range from a duo with vibraphonist Bobby Hutcherson to a 16-piece band featuring three French horns, three trombones, and three trumpets. And, of course, there's Tyner's solo piano. The most striking thing about this cllection is the difference in mood between the one cut in which Tyner uses Elvin Jones on drums, and all the other cuts, in which he doesn't. McCoy plays forcefully and well throughout, but the only real magic on the entire album happens on this single cut with Jones on durms, John Coltrane's tune ''Impressions''--shades of the Coltrane years.