In Fallout 4, most modifications for projectile (non-energy) weapons require only the Gun Nut perk. However, some require both Gun Nut and Science!, which normally is only used for energy weapon upgrades (I think recon scopes need both, for example).
As I'm considering starting over on a new character, and having no intention of using energy weapons, I'm debating not getting 6 points in Intelligence.
Then, as a purely projectile (or melee) weapon focused character, which modifications will I be unable to craft for my weapons if I don't have the Science! perk?
Best Answer
You wouldn't be able to craft night-vision or recon scopes on any weapons, that will be the majority of what you'll miss out on. The only other non-energy weapon is the Junk Jet which requires 1 point in Science! for some damage upgrades.
Power armor as well, requires Science! for some upgrades. Everything else requiring Science! are energy weapons.