Get yourself a pair of G1 Plasma Slug Rails. 3.6km is plenty of range and practically infinite ammo for practice.
Not always true. When the effect was new, i engineered an imperial hammer with plasma slug rails for my Imperial Courier. Turned out that this weapon drained my fuel like crazy. I actually had less shots than before.
Of course, that's a very specific combination. On any ship with big enough fuel tanks plasma slug is great, but i just thought i'd point out that there are setups where it actually reduces your number of shots.