Rule of cool, my friend. The idea of them directly shooting back is way better than evasive action.
Although I’m pretty sure the whole “gravity is different in the turrets” thing was mentioned in the Star Wars novelization, I believe it was also confirmed in the trilogy of Han Solo novels by Brian Daley.
Incidentally, those books also made it clear that even a perfectly respectable passenger liner would normally have a gun turret or two, just in case of the aforementioned space pirates. So, a freighter with some guns on it wouldn’t be quite so obviously illegal as it would be in this time period in this galaxy. Sort of like merchantmen in the “Golden Age of Piracy” I guess. (Han and Chewie do run into trouble in one of those books, not merely for having guns on their ship, but for–among other things–having a ship that’s too heavily armed for its class. And even for that, there’s a “waiver” list they can con their way onto.)
I’m pretty sure a “targeting computer” would do a way better job of putting a missile into a two-meter-wide shaft than even the most hotshot midichlorian-rich strong-with-the-Force pilot. And they have droids with strong A.I.!
I guess that’s why Star Wars is cooler than Star Trek. In Star Trek, they just say “Fire!”
/duck
They were actually more like the remotely controlled guns in the B-29 and P-61 than the ball turrets in the B-17 and B-24:
And yeah, once you can generate artificial gravity (whatever that is) you can direct it any way you want.
Surely, they would be space guns.
Since Han was a smuggler, and the gun turrets were visible to inspectors on the ground, I would expect them to be standard issue for that type of ship, or the MF would be virtually screaming “I’m a smuggling ship!” to anyone who looked at it.
And the design of the turrets was probably just cooked up by the model makers who wanted something ‘cool’. I wouodn’t be surprised if they kit-bashed them from some WWII models. Since all the dogfighting in Star Wars was shot as basically silly WWI and WWII aerial manoevering, a couple of twin-gunned turrets with large visual sights were perfect.
In real life, a space battle would take place at ranges and speeds such that you’d probably never see your enemy visually, and certainly wouldn’t be able to manually track and fire on them. But that makes for boring visuals.
Ahem. Quad-gunned turrets.
Dang, I think I need some more tape to hold my glasses together…
Yeah. Han’s guns might be souped up a bit so they’re more powerful than a standard freighter would have - but Han makes sure that those modifications aren’t apparent during a typical inspection.
“And way you want” does have some engineering limitations, no matter how the gravity is generated
If you make a room, and put gravity generators on all 6 walls, normal to the wall, you’re going to have a heck of a time moving around. Your head will be pulled to the ceiling at the same time your feet are being pulled to the floor. And if you walk close to a wall, you’ll fall into it. The difference in gravity between your head and your feet will make life “interesting”. (unless you’re Fred Astaire!)
The same goes for the MF guns if the gravity in the guns isn’t “up and down” relative to the main deck. The main cabin and gun gravities should interact and give weird effects in certain spots of the ship. And the transitions would be weird.
I’d assume the generators would be programmed to avoid such situations. Otherwise, it’d be poor engineering.
“The gun turrets have their own, independent artificial gravity fields, separate from the one that provides gravity to the rest of the ship. This allows the gunner to rotate the gun through it’s whole field of motion without becoming dizzy or disoriented. Or falling out of their chair, since those thing apparently don’t have seat belts.”
This is pretty much how I figured they worked
Though when making the original movie they hand-waved a lot of it away as fictional shenanigans, over time, as they established the Star Wars universe more definitively, they had to nail a lot of this down. In particular, when rebuilding the Falcon for the sequel trilogy, they redesigned the exterior to be easier to set up and relocate for shooting each movie, and then again when building a believable interior for the ride at Disneyland Galaxy’s Edge park, but most importantly when considering the early version we see in the Solo movie.
Basically the gravity field in the gunner seat is at 90° to the rest of the ship, so that their heads are basically oriented towards the forward direction of the ship, their feet oriented aftwards. I am basing that on the access ladder being oriented opposite the cockpit gangway.
As is the cockpit of the TIE Fighter. (And tons of other things in the Star Wars movies are based on weapons from World War II - isn’t Han’s pistol basically a Mauser Broomhandle with a few cosmetic upgrades?)
Although I never read any official back story material for Han Solo, my understanding from bits and pieces of ‘canon’ that I saw online over the years was that he was a former Imperial pilot. Presumably of a TIE Fighter since that seems to be the only “fighter” vehicle operated by the Empire that would require an individual “solo” pilot to maneuver it. When I saw the Solo movie (which I loathed) I was disappointed that they made him some kind of low-level infantry soldier. If I remember correctly, it was even below the level of stormtrooper, their gear was much cruder and they fought in trenches.
I don’t know why the hell they chose to erase the old canon and make THAT his origin story…but then, many of the choices of the people who have made the new Star Wars (and Star Trek, for that matter) features, elude me…
I lost interest in both long, long ago… 
As someone else mentioned, the Millenium Falcom is essentially a souped-up tug boat: massive engine in a small ship meant for moving shipping containers around.
Lando added the turrents later; as a smuggling ship keeping them hidden was probably more important than maximizing functionality. It’s not terribly surprising they are awkward to use. Han activates one from the cockpit in ESB though so they must have been somewhat computerized.
Actually, from well before even WW I: Mauser C96 - Wikipedia
That wasn’t one of the turrets, but a little pop-out underside blaster cannon (at 2:56 here): https://www.youtube.com/watch?v=shl31rC-aYg
Link to the relevant scene in the movies.
It’s pretty clear that the artificial gravity shifts in each of the turrets so that the gunner is oriented in such a way that his field of view is in “front” of him. i.e when sitting in the dorsal turret, the gunner is facing “up” relative to the cockpit of the Falcon but feels like they are oriented normally.
Now the question I have is - is the gravity oriented to the moving swivel chair so that the gunner always feels like they are pointing the gun straight ahead (like the ball turret on a B-17 bomber)? Or is it always pointed “down” relative to the Falcon so the gunner has a sensation of moving with the gun, like the door gunner on a helicopter or the waist gunner on a B-17?
I might think that might be a bit disorienting to the gunner. Not so much to Luke and Han in space where they would only experience a sense of movement when background of stars moves when the Falcon banks or pitches. But a lot more for Finn staring at the ground racing past, trying to engage TIE fighters directly behind him.
The big stormtrooper rifles are also based off the German Maschinengewehr 34 machinegun. The smaller E-11 blaster rifles are based off of British Sterling Mk IV submachine gun.
Also, Han was an Imperial pilot until he got shitcanned from the Academy and sent to whatever that unit of low-level light Imperial infantry was called. Which makes sense. I would think Stormtroopers are more like elite Naval infantry - equivalent to Marines or Airborne troops.
My WAG is those turrets are a standard option for a ship of the Falcon’s class. The ship design is very modular and customizable and with the access tunnels and weird gravity orientation, they are definitely inherent to the structure of the ship. Not something just sort of bolted on.
Not to hijack, but that kind of thing drives me nuts. Star Trek is one of the worst for that. Spaceships capable of several multiples of the speed of light, bearing weapons with ranges of thousands of miles, facing off from 500 yards at the relative speed of an 18th century Man ‘o’ War. Takes me right out of it.
Ok, rant over; I’ll bugger off now.
The shot of Luke entering the ventral turret shows how the gravity shift occurs: he starts by descending the ladder from the main deck, but when the camera cuts back to him he is clearly bear crawling backwards into the turret room. For Luke, it would feel like going down a vertical ladder that was being pitched down to the horizontal. From a practical standpoint, it would make sense to have the ladder rungs end about halfway down so they aren’t in the way of the gunner shuffling backwards into the turret.
Han’s situation would be slightly different. He would be climbing a ladder that pitches over to horizontal, so he’d emerge into the turret room head-first, facing the turret’s ‘floor’. It would make sense for him to flip onto his back at the last moment and grab a bar up on the wall near the ‘ceiling’ to pull himself into the turret. Sort of like the grab bar over the hatch here