The flow of gas–particle mixtures through an axially symmetric nozzle is analyzed. The particle behavior is considered under the condition where the velocity and temperature lags are small. Particular attention is paid to the particle streamlines, and the problem is solved only for the particle streamlines in the first approximation. It is rigorously proved that, when the impingement of the particles on the nozzle wall occurs in the supersonic region, there is an upper limiting point (line) in the wall region where the particles can impinge. The location of this point (line) does not depend on the particle size, but only on the nozzle geometry and the equilibrium reservoir conditions.