I remember being unstoppable in FO3 with A3-21's plasma rifle. Its firing rate is in this hard-to-hit sweet spot of two shots per second, and it's semi-automatic. The precision of repeated mouse clicks decreases as the interval between them increases, and the 500ms interval seems to afford me just enough precision that I can fire it effectively, but only with a bit of practice. That makes it very satisfying to use. In NV, the firing rate was decreased, so my reactions are no longer precise enough to get the optimal firing rate, which kinda sucks.