It's about time I give a review of my experiences with the Assault weapons of Battlefield 3. Myself being a professional Assault player for this particular game, I've made use of the rifles quite extensively. Let me share my experiences with these weapons, and perhaps persuade a few of you to try them out.
M16 Series[]
In game, the M16A3 and A4 are considered the same weapon as far as stat tracking goes. The difference between these two weapons is that the A3 is automatic and the A4 is burst only, but both have single fire mode if desired. For my A3, I find it to be a great all-purpose rifle. It's accurate, controllable, and fast. Firing it in bursts is the best bet. The A4, however, being 3-shot burst only, is best suited for medium-long range combat while the A3 can work at short-medium range. Although, that isn't to say both weapons can fill either role just fine.
AK-74[]
The AK-74M is a wonderful weapon. It's rate of fire is fast, but not too fast, so you won't throw yourself off target if using it full auto. Depending on your preference of sight, the AK-74 can fit any role. A strong zoom will let it shine at longer ranges, while a 1x standard sight can let you shine just as well at close ranges. Any combination of attachments, really, can turn this weapon into whatever you need it to be.
M416[]
The M416 is a great medium range weapon. It's very easy to control and does great work at dropping targets, even at full auto. It has a 3-shot burst mode, should you desire, so it can fill any role with whatever attachments, much like the AK-74. I have nothing but good things to say about this weapon.
AEK-971[]
The AEK-971 has got to be one of the easiest to control weapons available. At full auto, it makes short work of any opponent at medium range, even felling multiple hostiles without even letting go of the trigger. Be warned, however, as it's fast rate of fire will empty the weapon quickly. It's iron sights are the best around, being very open and easy to use. Coupled with a laser, the irons function better than any of the 1x sights, in my opinion. The AEK's fast fire rate and tight spread lend well should you desire a silencer, too. Be careful, though, as the silencer will prove detrimental for automatic fire. I recommend a grip to control muzzle drift.
F2000[]
This is the run-and-gun weapon of choice. The F2000 has a great quick rate of fire with a tight spread and easy to handle automatic fire. At medium range, the F2000 handles great. Compared to the AEK, the F2000's advantage lies in firing while on the move, running from cover to cover up into close range, while the AEK fares better being fired from a stable stance. But don't think that being on the move is the F2000's only niche. Putting a Bipod on the F2000 makes for an amazing long range weapon. The very little recoil and already tight bullet spread make for a deadly stationary weapon when stabilized with a bipod. Also, because the Bipod will not have any counter-effects when not in use, it gives you the option of using the same weapon for run-and-gun and stable fire-from-cover.
AN-94 Abakan[]
The Abakan is a wonderful weapon once you get the hang of it. It's cluttered irons and hard recoil are a quick turn off, but stick with it and trust me when I say it gets better. The Abakan has the least recoil of all the assault rifles. Now, if you ever fired the thing, you'd want to call me out. But listen here. The two-shot burst has the least recoil because as soon as you let go of the trigger, the recoil settles. At range, this allows you to take deliberate and precise shots with extreme accuracy to fell any opponent you can see. Any kind of scope is best, leaning toward the 3.4x PK-A or 4x PSO-1 if you want a bit more zoom. I recommend staying away from using the Heavy Barrel as it makes recoil much too annoying. A grip is not necessary as 2-shot burst has no horizontal muzzle drift in the first place.
KH2002[]
The KH2002 is an M16A4 built backwards, essentially. It's bulpup design prevents it from using an underslung rail, and also gives it a longer reload compared to conventional rifles. But, the KH2002 has very little recoil and works like a charm even though it's stuck on 3-shot burst. All shots land in a tight spread. Although it's cluttered irons might turn you off, once you get your hands on the 4x PSO-1, you'll never be able to take that scope off. It only takes 10 kills to unlock it, so stick with it!
G3A3[]
The G3 is chambered with a full power 7.62mm NATO round, giving it unrivaled stopping power. But this power comes at a price. The G3 is stuck with a small 20 round magazine, slow rate of fire, and horrendous recoil. Until the update roles around to give this gun a buff, it's easily outclassed by any other weapon in a face-to-face combat scenario. But don't let that turn you away just yet. When used with discipline and deliberate, controlled bursts, the G3 is a force to be reckoned with. And it's great stopping power lends well to close range combat, should you find yourself in tight quarters. Be warned, however, that this weapon has a long reload time, especially when reloading dry.
Mounting this weapon on a bipod is a marksman's wet dream. I suggest either a 3.4x or 4x scope when doing this. 6x scope is also a good idea, but may come to bite you in closer rages.
FAMAS[]
You want speed? You want control? You want French? The FAMAS is a quick, strong, and awesome rifle. It comes with all three fire modes available and works like a charm at medium ranges. This gun, however, has no rail and starts with terrible irons. Once you get in to it, you'll love the thing. But note its drawback: the weapon has bad performance at range unless you take very deliberate shots.
Mounting this weapon on a bipod is a great way to keep it under control.
L85A2[]
It's British, it's bulpup, it's easy to control, it's an L85. The L85 is, by far, the easiest weapon to control at full auto. Its rate of fire is just right that it can be fired in sustained bursts and still maintain precision without making you feel like you're losing control. Horizontal shaking can be annoying when firing, but just know that it's only visual, and shots keep on target.
AUG A3[]
The AUG is a great choice for players who have the discipline to fire in controlled bursts even without a fire-mode switch. In bursts of 5 shots, the AUG maintains a tight grouping and stays lethal and on target, even with a silencer mounted on. To be honest, the AUG is the only assault rifle I can stand to use with a silencer. The AUG is also the only bulpup weapon available that can fit a grenade launcher on it. This weapon shines best in medium range engagements, where controlled bursts eliminate targets with precision.
SCAR-L[]
The SCAR-L is a accurate weapon for the most part. When fired at full auto, the accuracy degrades quickly, but its still enough to work at close range. The weapon shines when used with a medium powered scope, like an ACOG, and used to pick off targets from a distance. It can also fit a grenade launcher.