I was at a certain part of the game when I really noticed this, but I went through over a thousand rounds of 5mm so quick fighting Sytnh's. I also never use a minigun on any legendary robots, I just use a missile launcher. I haven't come across a free gatlin laser yet, I am thinking id be more cost efficient to use a gatlin laser vs robots. Vs Legendary Deathclaw's a minigun tears them to piece, but vs robots it seems wasteful as you go through so much 5mm to take one down.

Like 5mm is cheap and cost efficient if your shooting the right type of enemies. So if a minigun can handle super mutants and deathclaws with ease, then you'd want to save your better more costly weapons (gatlin lasers etc) and use the minigun instead. However, if its robots using a minigun seems to be much more costly then using a energy based weapon.

The Gatling laser (with Charging barrels mod) is just flatout more cost effective than the Minigun.

Only downside is that the gat laser uses fusion cores as ammo, so if you find yourself unable to keep up with power armour needs already, a gat laser is not for you.

Thanks, yea I don't have any problems with fusion cores, matter of fact I have never ran out fusion cores and my character revolves around using power armor.