I just like to use one weapon and master it so I can use it effectively everywhere. I play TR and my choice was clear: Trac-5 with a foregrip. The weapon can hold-up at CQC hipfire quite well and close-range aimed fire is deadly as hell. It is quite accurate to surprisingly long distances. It's weakest point is "the distance where without laser sight hipfire is not enough yet aiming can be disastrous". It is a very small area of weakness imo and I think the weapon is extremely versatile and powerful. I feel that one can kill (note: kill, not farm) people with trac-5 to almost as long distances as AMC can. This is my experience and opinion with the weapon with I have 15k kills and counting. I only play engineer and thus I have more "trade-fights" than LA overall and that is why I probably prefer a more powerful weapon. I don't have much experience with other factions and thus I would like to hear what carbine you would consider to use if you had to use just one carbine for every situation.
NS11C. It has a relative low rate of fire BUT it has 0.75ADS movement multiplier and a laser like acuracy. So in close quarters its not comparable to high rate fire weapons but in short-mid, mid, and mid-long ranges there is no better carbine in this game.
GD7F hands down for short to midrange Pulsar c hands down for mid to long range (or short if you have decent aim and not engaging heavies) Eclipse for longest single life kill streaks.
VS: Pulsar C has a good balance of accuracy, decent TTK, and is all around not too shabby. TR: Jaguar 4 life, has good midrange power and is very good close up. Easily the best TR carbine. NC: Can't go wrong with the Mercenary. Otherwise you can try the ACX-11 since it is pretty close to the Mercenary in DPM and DPS. Both are good guns.
I'm torn between the Razor and the AMC. However, I really don't have enough experience with VS carbines to really make a choice from anything in that armory.
Frankly as an NC I don't like the GD7F at all really. I know it's a popular weapon and generates a lot of complaints from non-NC, but I honestly wish it would go away so we could have a chance at a better weapon.
There are two schools of thought when it comes to carbines. 1. Where you try to ignore carbines' downsides, and just try to get the most effective range out of it, to have a better chance when going against ARs / LMGs at range. Precision carbines work best for this purpose. Razor / Pulsar C / Cougar. 2. Where you embrace carbines' strong side - their affinity for CQC, and try to work around the short effective range. For TR - Jaguar, both ALS and Forward Grip will work good here. For NC - GD-7F. For VS - Serpent / VX6-7. Higher DPS / faster reload, take your pick. Awha?.. "Better weapon"? Better at what? At CQC? You don't get better at that than GD-7F. Bandit is always there as a high damage / low RoF counterpart. And mid/long range carbine selection is well covered for NC. With NC having the most variety in their weapon selection, I think you can hardly complain.
All-rounder? The default one. No, really. The starter carbine in your arsenal is, IMHO, more or less an awesome all-rounder weapon. You can run with it all day, everyday, everywhere, and it will be able to pull its weight regardless.
The AC-X11 is like having Katy Perry covered in cream and honey. You blow your load fast but it was damn worth it
Ns-11C 1x scope, laser sight, compensator, HVA. If it's for using only one carbine, that's my favorite.