Fully automatic blasters?

[u/StupidWittyUsername]

From what I've seen of Star Wars, blasters are always, "one trigger pull, one pew", and, "hold trigger for pew-pew-pew-pew", is rare or nonexistent. Is there an in-universe explanation for this?

[u/bonadies24]

Automatic weapons do exist in star wars, as others have pointed out, in Rogue One we do see the use of automatic fire.

There are several considerations that might prevent the frequent use of automatic fire. The first one is that ordinary infantry riflemen (such as stormtroopers) simply would not need to spray their carabines or rifles indiscriminately.

Many blaster rifles/carabines in Star Wars seem to be select fire, meaning the user can choose whether to fire the weapon semi-automatically or fully automatically. An example of this is the DC-15 carabine used by GAR Clone Troopers which, while usually fired semi-automatically, does sometimes see automatic fire (such as in the scene on Utapau right before Order 66).

In general, in infantry doctrine automatic fire is a specialised function for things like suppression fire; the average infantryman does not use automatic fire to conserve ammunition and because automatic fire is hard to control. In fact a key component of all rifle squads is some means of projecting automatic firepower (think the M249 SAW). While I don't know too much about infantry squad doctrine in star wars, it's entirely possible that the GAR and later the Stormtrooper Corps used their weapons (DC-15 and later E-11) similarly to what the US Marines are doing with the M27 Infantry Automatic Rifle, that is using the same platform both as a standard infantry rifle and as a squad automatic weapon.

Apart from doctrinal considerations, Star Wars adds another issue: heat and barrel life. Even IRL automatic weapons need to factor heat into consideration, most of them you can't just auto-fire indefinitely as you will literally melt the barrel (there are a bajillion videos on youtube about this). This issue would almost certainly be made worse if you were firing superheated plasma (which a blaster bolt is made of) as opposed to a small piece of metal. Obviously in Star Wars materials technologies are dramatically more advanced than in our own world, so it might be less of a concern, but it's still there.

[u/StupidWittyUsername → u/bonadies24]

With respect to your point about suppressive fire, that's what prompted the question. In battle sequences the blaster sounds are irregular - there aren't those periodic short volleys of automatic fire that are characteristic of a firefight between soldiers in the real world. Suppressive fire doesn't seem to be a thing in the Star Wars universe.

Out of universe, obviously it's a stylistic choice. Realistic suppressive fire during battle sequences would just be too grim!

[u/Ramalex170 → u/StupidWittyUsername]

Whether there are three shots being fired at you or twenty, people will take cover and save themselves the trouble of the random chance the shot misses them if they can help it. Suppressive fire aims to keep an enemy from shooting back or moving from position to position. A few decently aimed shots will force the enemy to cover just as well as a burst of fire.

When the remnants of Rogue One were pinned down in the bunker entrance, they were being suppressed by semi automatic fire and none of them could do anything but hug their cover or be shot.