We have studied stress overshoot behavior in startup shear of four monodisperse polymer melts with a range of chain entanglement from Z=24 to 160 entanglement points per chain. In the elastic deformation regime defined by γ̇ τR>1, where τR is the Rouse relaxation time, (i) the peak shear stress σmax scales with the time tmax at the peak to −1/2 power, in contrast to an exponent of −1/4 in the viscoelastic regime (for γ̇ τR<1), (ii) σmax changes linearly with the elapsed strain at the stress peak γmax, which scales with the applied shear rate as γ̇ 1/3, (iii) a supermaster curve collapses time-dependent shear stress growth curves up to the stress maximum at all shear rates for all the four styrene-butadiene rubber samples.