The M-ary sequential probability ratio test MSPRT is used to recognize unknown non-cooperative radar targets. Radar returns representing the unknown target backscatter coefficients are tested sequentially using MSPRT. At each stage of the recognition process all observations are used in MSPRT, if no identification decision can be made, additional information is requested and MSPRT is implemented again. The goal is either to minimize the number of observations needed to identify an unknown target assuming a certain predetermined error probability, or to minimize the probability of error assuming a predetermined maximum number of observations. The experimental phase of this study involves radar cross-section signatures of four commercial aircraft models recorded in a compact range environment. Scenarios representing various degrees of azimuth uncertainty are examined in this paper. In all cases, it is assumed that the unknown target is corrupted with additive white Gaussian noise.