Except the entrance hole of bullet, there is flower-like pattern around the entrance when shooting by rifle equipped with flash suppressor in a near contact distance on skin. The distinct, seared and soot pattern is produced by the heat and gas emerged from slits of flash suppressor. In a suspect rifle shooting case, however, an expert of firearms testified that there was only flower-like soot pattern and no burn pattern left if shooting by rifle equipped with flash suppressor. To clarify this improper testimony to influence the verdict in the future, this study demonstrated a test on pig skin by M4 rifle equipped with flash suppressor in a near contact distance.