Ok, so I need a good Long Range based carbine for NC, it can be NC or NS. I've been looking at the AC-11X, the Razer and that's all i've seen for good long-ish range carbines. I need it mainly for when I'm trying to be a "sniper" at a slightly shorter range, but with more mobility. I already have my idea for a explosives expert loadout (mainly Gauss Compact S, with Underbarrel Grenade launcher, Grenade Bandolier, and C-4)
https://forums.station.sony.com/ps2/index.php?threads/nc-long-range-carabine-ac-x11-or-razor.209839/ http://ps2guides.besaba.com/mechanics#carbines
If your going for a full explosive load out don't forget to equip a crossbow with explosive bolts. As for your question I think that you would be better looking at the NC guns for long range than the NS-11C its pretty accurate but its velocity is too low to be of much use at long range.
The AC-X11 is excellent for ranged combat. It handles fairly similar to the Gauss Saw, so the recoil is pretty snarly. I use mine with the Advanced Foregrip, Compensator, and 2x reflex.
AC-X11 - the Razor is just weak weak weak, and the enemy will likely run away on you before you can drop them unless you can consistently land headshots.
Has HVA available, which is almost a must run on this weapon as it ups velocity to 550ms and maintains its accuracy for the most part. Also has semi auto mode, where it is pin point accurate at medium to longer ranges.
After playing with both the Razor and the AC-11X I definately like the Razor better. the AC-11X even with Compensator, 3.4x Sight, and AdvancedVertical Grip just has too much recoil... and I havent even certed out the Razor, i just have a 4x Sight on it.