It is? I always thought that would be the 7.62 NATO.
No, althought it was intented to be. The recoil impulse is just too high and heavy for it. If it were the ideal bullet, it would be used by every assoult rifle today.
Originally, it was the 7x43 British for the EM-2. Canada, Britain and Belgium was satisfied with it. Of course, Americans did what Americans always do: announce that the solution that works for the rest of the world to not work for them and stick to a solution that doesn't really work for them either, but by God, its American. This is what resulted in the 7.62 NATO, which is too strong for full automatic fire.
Of course, the solution didn't work, because of the high weight and recoil. Thus, Americans again did what they often like to do, is instead of a slight adjustment, they fall on the other side of the horse, hence the 5.56 NATO. This too does not work quite the way it should, for reasons I won't get into right now.
Of course, if the Americans would have shut the fuck up and would have adopted the 7.4 British along with the EM-2, there wouldn't be this mess and we wouldn't see steps of idiocy like the M4, where they had to cut the barrel in order to do something that adopting a bullpup configurations would have solved.
Read the story here (the full story is only within the book, which if you excuse some wanking, is quite good):
http://www.quarry.nildram.co.uk/256brit.htm
I recall that SOCOM highly favours the 6.8 Remington.
It's also said to be some kind of fully-automatic sniper rifle, if I'm not mistaken, which frankly is ridiculous given its effective range in the game and the calibre of the round fired. Most military sniper rifles I'm aware of are large-calibre weapons.
Depends on what you define as "sniper rifle" and what ranges. In short, urban ranges, you don't need a true sniper rifle or person, just someone with a above-standard accurate rifle and skill.
You're exaggerating severely. They could benefit from a machine gun that could auto-fire more often than the jack-of-all-trades rifle to lay down suppressive fire.
Suppressive fire doesn't quite exist in X-com, mostly because of the fact that the enemies don't tend to take cover, thus again, becoming a pointless weapon.
Furthermore, you can hardly fire a machine gun from the shoulder and most of the scenarios are too fast to lay out a machine gun.
Plus, unless you are willing to sacrifice the utility of three other members, the bullet will be the same as the one used from an assault rifle. What advantages there when you already have a decent carbine that can also deliver automatic (or at least, burst) fire?
They could benefit from a sniper rifle that can actually hit and kill things at a reasonable distance.
Sniper doesn't mean "snap-shooter". Snipers have to aim their rifles just like everybody else and the main reason that teams often miss is that they're don't have time.
Plus, a sniper rifle would be make the sniper even more impotent against treats than otherwise.
They could benefit from a slug-firing shotgun that can actually kill things at close range. Etc.
Actually, I would argue for an automatic shotgun or even semi-automatic shotgun using specialised ammo. However, this again, would be unwise:
Automatic shotguns would have to fire either buckshot or slugs. Buckshot might not stop a wild boar, never mind an genetically-engineered tough-hided alien soldier. Plus, buckshot degrades with distance.
I would have to check data on this, but I'm not sure a slug would offer that much better performance against a rifle bullet.
The only possible advantage would be special bullets. Special bullets would either be not reliable enough, both the bullet's effect, accuracy and the gun itself. If you were to take maximum advantage of special bullets, you would have to switch to them mid-battle, an obviously unwise idea.
Personally, an underbarrel grenade launcher would have been more pointed effort, but I can see how that would screw with game balance, thus cut.
Furthermore, they could also benefit from an order of Dragonskin to replace those silly pajamas they wear.

Dragonskin is intended against bullets and shrapnel, not plasma fire or claws of monsters.
That, and Dragonskin was made
after X-com was published.
The level of abstraction is so high that a weapon that is intended to be a minigun is limited to some six rounds of fire in a turn from a stationary position.
The auto-canon is a minigun? I thought it was an automatic cannon, with the explosive bullets and all.
Also, the reason for that, is game balance.
If you had a weapon that would obliterate anything it is pointed at, there wouldn't be much fun to play the game, now would it?
an anti-tank rifle (which have been obsolete for a while, anyways, if I'm not mistaken.)
I recall that they are still issued and made. They don't work against tanks anymore, but against vehicles (like, say, the multi-million dollar fighter jet that can be turned into multi-million dollar scrap by one bullet) it still serves well. Plus, it can still ruin anybody's day if they happen to catch a bullet from one of these.
What? These aren't "fiddling details that make no difference." They're realistic military hardware, which is quite a bit more dangerous than the stock shit they force on you.
Realistic isn't always good for video games. They can be good measure as immersion, but the point of a game is to be an actual game, not a simulator.
If you want realistic, get a combat simulator, I think you can actually buy simulators that actual soldiers learn combat with.
But the rest of us, including this gun-nut, is willing to forgive or even embrace unrealism for the sake of fun and a good challenge.
The fact that I am limited to a measly jack-of-all-trades-master-of-none rifle with a non-standard calibre and ludicrously tiny clip is too much, especially when a wide array of superior weapons for close-quarters combat already exists and has existed for decades.
Which will suck for one reason or another. Why not just make ONE weapon that sucks just a little but is good for any situation, rather than make one gun that's only good for one kind of situation.
I may be going over the expansions of the developers here, but try this:
Imagine yourself as someone who has developed X-Com, the institution. You are given the task of finding the best weapon possible for soldiers facing the unknown.
Here is what you know:
- The possible fights will be carried out in relatively short ranges, likely not exceeding 300 meters.
- Fights will happen in any area, in any time. Fights are likely to happen in urban areas, so size is a factor.
- Fights will be short, but highly intense and thus bullet must count.
- Your enemy is likely to be better equiped and armed than you are.
- Your enemy is unknown and its tactics are unknown.
- Since we operate in secrecy, our logistics should be as simple as possible.
- Requires minimum cross-training.
- Requires minium R&D, so it can be put into service quickly put into service.
So, what are you gonna do?
Are you gonna issue 5 different weapons, or are you gonna try and make a single weapon that can perform all roles fairly well, so that any soldier can account for any unexpected situations?
Personally, the only flaw I see in the X-com weapons is:
- Instead of a long-range scope, use a red-dot reflex sight that can adjust between 1x and 4x. This might be an invention of the last couple of years.
- Put in an underbarrel grenade launcher, allowing the use of a variety of grenades.
- Allow the use of a drum magazine. Risky and bulky, but the higher ammunition cap might be worth it