I downloaded the wiki beam fire chart, and another thing bugs me now:
an 80cm Gamma ray laser could reach 18 mil km, but maximum beam fire control will reach 1. 4 mil km only. . . isn't it a bit too much overkill?? I mean, with a Gamma ray laser i will only be able to fire on a target at no more than 1. 4 mil km away??
Or will i be able to target and hit (maybe with a penalty) to targets at 15 and more km away?
No you would only be able to hit anything at 1.4m km (and even that quite seldomly). A 30cm X-Ray Laser would extend to that range, so one might wounder why its useful at all. But Laser damage drops of lineraly until it hits 0 at the maximum range, so the 80cm Gamma Ray would still be able to do 92% of its damage at that range, while a 30cm would only do 16% of its inital damage (which would be smaller to begin with).
Also, if you are laging behind in FCs you might want to consider carronades. Punny range, but very good initial damage.