Ultrasonic-attenuation measurements have been carried out on the magnetically reversible, type-II superconductor V - 5.6-at.% Ta with both a high Ginzburg-Landau parameter (${\ensuremath{\kappa}}_{G}\ensuremath{\approx}5$) and the Bardeen, Cooper, and Schrieffer (BCS) coherence length 5 times the electronic mean free path. The electronic attenuation $\ensuremath{\alpha}$ in zero magnetic field below ${T}_{c}$ is BCS-like, giving a zero-temperature energy gap $2{\ensuremath{\Delta}}_{0}(0,0)\ensuremath{\approx}3.6{k}_{B}{T}_{c}$, and in the normal state has the theoretically predicted dependence on $q$ and $l$. The upper critical field ${H}_{c2}$ could be deduced from the attenuation data to an accuracy better than 1%, and its temperature dependence agrees well with type-II theory without $p$-wave scattering of electrons. Use of the measured normal-state resistivity and ultrasonically determined values of ${T}_{c}$, ${H}_{c2}(T)$, and $\frac{\ensuremath{\partial}\ensuremath{\alpha}}{\ensuremath{\partial}H}$ at $H={H}_{c2}$ inserted in an ultrasonic-attenuation theory due to Maki enabled the calculation of an Abrikosov-Maki parameter ${\ensuremath{\kappa}}_{2}$, which agreed roughly with the ${\ensuremath{\kappa}}_{2}$ obtained in previous magnetic and calorimetric measurements. Thus, for $H$ close to ${H}_{c2}$, the data agree with Maki's dirty-limit ($\frac{{\ensuremath{\xi}}_{0}}{l}\ensuremath{\gg}1$) theory, which predicts a linear dependence of $\ensuremath{\alpha}$ on $H$. At fields farther from ${H}_{c2}$, $\ensuremath{\alpha}(H)$ deviates from linearity and appears to fit empirically a parabolic function of $H$. At very low fields $H\ensuremath{\gtrsim}{H}_{c1}$, the $H$ and $T$ dependence of $\ensuremath{\alpha}$ is in apparent agreement with another theory. Physical insight into the behavior in this region could be obtained with a model in which vortices are replaced by cylinders of completely normal material imbedded in a superconducting matrix.