I like the way these are explained in the book, but I had to elaborate a bit on them for my players because it seemed to be something that they wanted to dispute in order to get an advantage, or to ameliorate what they felt was a disadvantage. I consider the range categories to be abstract in nature, but also conforming to loose standards at times when it can help to describe a scene. I always consider range categories to be somewhat elastic, but I give them a median range description.
Example:any conversation that is accomplished using voice is almost always going to be at Engaged Range . That is fairly straight forward and I imagine most people would assume that, but for something like a tense stand off in a non-public (not crowded) place it could be at short range. Sitting next to someone in a speeder, playing a game of sabacc, standing near someone at a public terminal, talking to a bartender, or using a control on a wall are all obvious Engaged range situations.
Observing something requires getting close to it unless you have macrobinoculars or some other aid. Most beings with senses like human senses will move close to something to see details. If my players ask for details I will determine how close they need to be to the thing/person to see these details. Something like a personal vidscreen or a wall control box is definitely something you need to be at Engaged range to read if it has information on it that was meant to be read at say something like no more than 3ft. or a meter away. I won't usually prompt players who ask for details but instead I will describe them getting closer to the object as they observe details. If the object attacks or the area close to it otherwise becomes dangerous I know where the characters are in relation to it for the most part. When that happens one or more people will certainly explain that they were not near the thing, but I will weigh this against how they acted and whether or not they were interacting with the primary observer. Because this comes up, I will often ask for something like an old D&D marching order. I will ask them to describe the way the group is arranged, but I usually disguise it as wanting to know what equipment they have ready.
Grenades also brought this into consideration, as grenades do blast damage at Engaged range. I looked up the standard fragmentation grenade kill radius and it's listed at 5 meters, even though damage really should be possible at short range (up to 15m), and grenade fragments can travel as far as 230 m. So if you wanted to have engaged range be 15 m (45 ft.) there is certainly an argument for that to be the case. I figure that 5-15m is a good range for engaged range under most conditions. It takes one maneuver to close from Short to Engaged, so lets say a character is a good 20 meters from a target he wants to melee, it makes sense that some significant amount of movement would be required to close into melee or brawl range. It's not usually going to be a straight run in and hit type situation, the character will have to look for an opening, dodge or hide from other opponents, and make their way into a position to attack while defeating any parrying or dodging done by the target of their attack.
Short Range is going to be anything above easy walking range, or because of conditions, a dangerous space to cross. I use 15-30m as my guide, mainly because the two ranges on either side of Short are something I have more defined preconceptions of in describing. Short range is an easy pistol shot to my mind, and that's typically my frame of reference for it. It's also a good range for throwing things at a target. I have tried actually hitting things with a thrown weapon and to me 30m was a difficulty throw that required tossing the weapon up quite a bit to compensate for drop. Scoped weapons would have to use occluded eye for Short range as the scope is going to be a hindrance that close up, so I generally don't have them add bonuses for certain attachments at short/engaged. Sort is also the range I use for a standard wireless connection for datapads used in slicing. I don't allow long distance hacking of systems in order to keep the feel close to the movies.
Medium Range is the longest range for pistols I think (don't have the books in front of me) and so I'm thinking this should be a little further out. A .45 ACP round has a surprising maximum range of nearly 2000 yds if aimed at 24+ degrees. This means that pistol accuracy is more about the shooter than the bullet. But we could also assume that blaster bolts tend to lose coherency over distances of what are greater than what we typically see in the movies for non-vehicle blaster weapons. They seem to be some sort of plasma weapon so they could have a lot more energy to impart than a slug, but maybe they typically don't have the range of bullets because the bolt begins to be pulled apart by the environment if it continues to travel and doesn't hit anything. The shorter frame of pistols combined with standard firing positions and including the reaction of the shooter under combat stress make for harder shots than is optimal. Average max range for lethal shots for a shooter is 30 m. So to me given a weapon with plain old iron sights the medium range mark is going to be about there, say 30-50 meters. With a scope or futuristic targeting aids, a steady brace, a skilled shooter could be hitting at 200m if the target is visible and exposed, and not moving very fast or erratically. Because the Pistol and some Carbines have Medium as their maximum, I would say that having a high accuracy set of conditions would actually expand the Range Category for them in that situation giving the capacity for a shot at longer range.
Long Range to me is outside of casual shot range, this is a shot that has to be made using sights and scopes and with the shooter trying to stabilize the weapon as much as possible. I use 50m as the starting point for Long Range, but the median is 60-100m to me, because I think I figured out that the average hangar bay like the one in ANH would be about this wide. Long is the rifle range, so my inclination is to make it extend out to 400 m. This gives a good long range for shots, but it isn't so far as to make it ultra-long distance kill territory. It's also a good range for anti-vehicle weapons because it's not suicidal as a distance from the target for Anti-Vehicle Infantry.
Extreme Range is anything beyond a hard rifle shot out to the maximum effective range of the weapon. A missile tube could conceivably have a maximum range of 4 km easy given futuristic technology and propellants, which would put it's targets very far out of detail range of normal sight given standard vision. If you are shooting at airborne targets then such a weapon would probably go into Planetary Scale, but for ground targets most of the time its probably going to be something in the immediate battlefield area.
Would love to hear any tips about how you use the Range categories, from the ultra fast and dirty, to the crunchy and complicated. Thanks for any responses