I personally like automatics ALOT, ever since FO3.
Here i struggle to please both game effectiveness and my tastes, expecially considering how there's so small choice when it comes about automatic weapons >.<'
Decided so to use a submachine gun at the early levels, replacing it with a (modded with auto receiver) combat rifle once you can get the gun nut perk at level 3 to fix your weapon accordingly and access the almost endgame modifiers.
For the endgame you can mod to full auto the unique Plasma rifle you're going to find at the Institute's vendor, is named experiment-18A and its more than descent, even if not extestically good looking.
Otheriwse you can go with an automatic laser rifle but to mod those you need science! perk as well, and auto lasers burn through ammos really really fast.
Eventually you can tap with some perks in explosive for engaging from longer distances in order to save ammos.
I find the rank 2 explosives perk to be very good for my playstyle.
Eventually boost agility for vats and any crit related perk, compared to rifles you'll miss only about range.