A repeater or autoloader could work as well but the hair trigger just feels right.

As they shoot so often something like a hair trigger just adds to their already pretty substantial ability to dish out several attacks per turn. They can shoot twice per turn so 3 bullets per clip just doesn’t cut it. Skirmishers get an expanded magazine and a hair trigger. I have zero qualms cheesing banish with a repeater. Reapers get an expanded magazine and a repeater. Templars don’t and maybe can’t get anything. You generally always have something else you can do, so the default clip size and need to reload never feel particularly restrictive. A scope could work as well but between not having tons and the ability to boost aim via holo-targeting it’s a bit wasteful in my opinion. Machine Gunner abilities tend to eat through bullets so the idea is to make using them more frequently without drawback possible.

Grenadiers I generally go with a mixed set of expanded magazine and autoloader. The laser sight is for higher aim and crit up close, the stock is for some damage from a distance. I think the reasons are pretty clear cut. Snipers get a scope and either a high end autoloader or a high end expanded magazine. Less because they’re an amazing fit and more because specialists shoot more, have a decent clip, and are decent at mid range. Specialists I tend to use Hair Triggers, Reapeters or stocks.

Xcom 2 remove weapon mods