M increments and associated dynamic properties are transported across the boundary of a variable mass system, and this complicates the derivation and interpretation of equations of motion. Of course, various formulations of variable mass dynamics exist in the literature and in standard texts. However, ad hoc methods are generally applied to the transport problem, results differ greatly in form arid complexity, and the origin and significance of variable mass peculiar terms is often not clear. In this paper, a general transport rule is applied as a contribution toward unity and clarity in variable mass dynamics. Also, results are obtained in forms similar to familiar constant mass relations. These forms are convenient for analysis or simulation and for evaluating the relative significance of variable mass peculiar terms.