I just LOVE sniping from far distance and yet would like to know what weapon should i buy for easy sniping (12x) and gain alot of certs without being spotted/killed fast but more damage ?
All bolt action sniper rifles = 1hk when a headshot, 2hk otherwise. All semi-auto sniper rifles = 2hk with at least 1 headshot, 3hk otherwise. The sniper rifles that come with a scope pre-installed go up to 12x scope, otherwise they only go up to 4x. As for getting a lot of certs fast, there are much easier ways to do that than sniping.
As Soylent said, if you want to farm certs, DON'T go for a sniper. There are precious moments when you get severel quick and easy kills. But it's quite rare. I play the class for fun. If I want to farm a bit, I run as a medic or engineer in a tech plant attack. As for the rifles - I would recommend you to go for the cheap (100 certs) bolt-action rifle. M77-B I think) What's the point in sniping if you can't kill the target with a single headshot, right?
Both of the 2 bolt action sniper rifles with a pre-installed scope (since they can go up to 12x) do the job. The one that costs 1000 certs has less bullet drop, that's all.