1. That's why I specified rimfires. Some target competitions with rimfire cartridges (like .22LR) are "extreme range" competitions out to 200 yards--which is extreme for the .22LR, but not for, say, the 5.56mm NATO or a .300 Winchester Magnum.If your weapon is incapable of firing accurate above 100-ish yards (perhaps because it doesn't support aiming that well), why should you account for it?
And if you fire in vacuum, there is no wind drag or air resistance.
In a ship corridor there is air resistances, but still no wind drag.
And in deep space, gravity can have a much lower effect than on Earth for example.
The bullet speed also changes a lot in vacuum, mainly because the bullet does not need to push the air out of the barrel.
"Laser-bursts" also called "Laser-bullets" or "Laser-projectiles" and similar for all other Laser-like guns such as StarTrek-phasers or Masers that work at near-light-speed almost ignore gravity apart black holes.
A sniper riffle that shoots 2000m on earth at about 700m/s needs almost 3 seconds before impact and you need to aim it about 9m above the target.
In space, the same projectile would travel at much higher speeds and the chance to hit the wrong target continuously decreases as each shot has is a slightly different direction and targets are much further apart.
That's why you need a different classification for sniper/other guns with different environments (space, low-wind-corridors with airlocks each 100m) and different ammo capacities (that may hold up to 2000 charges or be able to accumulate charge for multiple shots at once).
2. A sniper rifle that shoots at 2000 meters with a muzzle velocity of 700 meters per second will have varying drop depending on the chambering, weight of the bullet, ballistic coefficient of the bullet, ambient temperature, moisture, and cross drift.
As well as the temperature of the bore--there's a reason snipers and competition marksmen take only "cold bore" shots.
3. Lasers aren't projectiles, but beams. The rare "laser bullet" is actually more of a charged particle weapon; as the projectile is visible, has kinetic energy and not just heat energy. In addition, lasers do not ignore gravity--the effects of gravity are simply less stated until you encounter extreme gravitational warping--200 gravities will bend light as badly as 1 gravity will bend the flight path of a solid projectile.
Back to the sniper discussion--The .308 Winchester with an average match grade projectile has roughly just about 460 inches of drop at 1000 yards. The 6.5mm Creedmoor has a drop of 280-ish inches with factory loads (not quite 200 inches less), and the 6.5 Grendel is roughly 330 inches of drop out of an intermediate rifle cartridge (the Grendel is a round designed for use with AR15 platform rifles with a simple barrel and bolt change) and [/i]10" close quarters barrel[/i]. This is why I specified the use in games--most games use an anti-materiel round or a heavy magnum round (.338 Lapua Magnum, or when "small" the .300 Winchester Magnum), rather than what is actually used and issued (generally the 7.62mm NATO/.308 Winchester--difference between the two cartridges is mostly chamber pressure and bullet weight).
Platform =/= dictate drop. Velocity at range and at the muzzle will account for some, yes, and those are platform specific; but bullet weight and ballistic coefficient (basically a measure of drag effects) will account for a lot more, and those are dictated by: chambering, bullet weight, powder charge, ballistic coefficient... a lot more goes into your ammunition than you'd think.
The reason the distinction between factory and match ammo was made above is that match ammo is specifically put together for a single firearm specifically, using measurements gained on a shot by shot basis to give it something it will eat reliably and accurately--though some factory ammo is labeled "match grade", rarely is it actually true match grade. Factory ammo, on the other hand, is mass produced and not held to the same precision standards--a factory 230 grain .303 British cartridge may have as much as a 5% difference in the powder load and bullet grain weight.
Ballistics is an absurdly complicated science, and long range (further than 600 yard) shooting is a very involved process--so while an issue military M4 shooting 5.56mm NATO 55 grain ball may be able to reliably ring steel at 650 yards with a good shooter, it's not the platform standard and hinges almost entirely on having a trained shooter behind the trigger.
And that's without me getting into barrel harmonics, recoil force (made up of backforce (direct rearward travel) and muzzle rise (upward rise of the muzzle)) the differences between a free float and bedded barrel...
Something of note--assault rifle chamberings are not limited to 100 yards like video games portray. The general engagement envelope of most assault rifle chamberings is out to 600 yards, give or take. Shotguns with a good choke can pattern buckshot at 75 (that is, a spread small enough to deliver most of the shot on target), slug will accurately hit out to about 300 with a good shooter... most "hunting" cartridges are actually more powerful and reach out to sniper rifle ranges (which is partly due to the fact that sniper rifles coopted effective hunting cartridges for their chambering). Most video game weapons seem to have been modeled after rimfires and airsoft toys with how short ranged and ineffective they tend to be (though Call of Duty type games really have a hard-on for making a 5.56mm NATO 8 inch barrel Colt Commando PDW hit harder and be more accurate than an M14 service rifle chambered in 7.62 NATO).
Basically, if you learned about it through movies or video games, it's wrong.