How do you counter a 'good' CQC sniper?

I don't think MAX really counts, may as well have suggested getting a tank.
Ans SMG infil might work but usually they carry a Commissioner, and those hurt

I guess I overlooked smoke, likely because you'd have to put it down ahead of time and usually that's a bit too late.

With the recent nerfs to the HA over shield lowering them from 750 to 450 this is no longer possible as a typical CQC sniper has a max damage of 750 (and also a 2.1x headshot multiplier). It would only work at range, where you'd be able to dodge the shots.

Regarding MAXes and overshields:

MAXes ... well... I don't think they really count in this discussion - if only because MAX is the counter to basically any infantry class. Sure, they all have various level of ability do deal with a MAX (and infiltrators least of all), but an AI MAX vs any other class it is fairly obvious that the MAX will always have the advantage unless the skill-level between the opposing players is very high. Smart BASR infils will not engage MAXes at all unless they are at a safe distance to take pot-shot at - and even then it's mostly as a token of helping the team. You aren't doing to duel a MAX down with a BASR unless he is totally helpless and unable to figure out where is being shot from - and even under those ideal cicumstances it will take a looong time to kill it.

Overshields do protect you from even headshots from BASRs. MOST BASRs that is, and only while the overshield is mostly full.
There are a few weapons that CAN kill through a full overshield, but those are exclusively long-range BASRs like the longhorn or whatever. You won't see those in CQC except as a desperation weapon.

However, it used to be the cast that you could tank a BASR headshot with an overshield fairly easily. Since the nerf you need like 90% or more juice left in the tank to take the shot to the head. There is a margin, but it's not very large. You can run into a room as a heavy and engage your shield to be immune from an instant-kill, but it won't last for more than a handful of seconds. It also makes you less mobile, and thus more likely to get hit - so it's a tradeoff. the rechamber time on even an CQC BASR is long enough to kill the offender, but he could always draw a sidearm to finish the job - and you won't have much HP left to tank that after a headshot.

-Stigma

I can't say I've had actual trouble with this. Don't get me wrong, I've been killed from relatively short ranges by Vandals (mostly) and other similar weapons. But when I return, the dude is gone. Probably killed by a teammate.

Having done CQC sniping before myself, I'd say the thing that gets me, is a load of people. The most I've been able to take out in close succession is 3. In those situations, there's more, and I'm running low on ammo (BASR have long as hell reloads).

If one was being particularly problematic, I'd spam them with stickies. Sticky grenades have long fuses and give time for the sniper to run. Problem for him, if he's moving he can't shoot, and that's when I'd run in. If you don't overthrow, you can literally toss two stickies and run by them while the sniper withdraws. Then finish him off.

Grenades are great for killing. But even better to use them for distractions.. most people think you'll wait till it goes off to rush in and prepare for that. That's when you flank around another corner or even charge them head on while they're still trying to get a safe position.

The close range variants have a maximum damage of 700, and they start dropping off at only 10 meters. Anecdotally, I have absolutely had no-kill headshots on shielded heavies from one side of a small room to the other.

Lol.

CQC snipers have a ridiculously short TTK. To counter them, you need

a) Something with a similar TTK: Shotguns for example
b) Something that can tank the damage while you kill them: Heavy shield
c) Something that allows you to ambush them and give you the advantage: SMG infils, stalkers, light assaults

Or just emp them and murder them with commie

That works too

It won't work against any full-shield heavy that has activated his shield within the last 5-or-so seconds no (aside from a few specialized weapons not commonly used in CQC). it will work against heavies with less than full health or less than full shields though.

Anecdotally I'd say firing a headshot against a heavy with shields up is maybe about 30-40% likely to result in a kill, but this is obviously very variable depending on your experience, server, ect. people tend to want full health before engaging, but random damage from exposives or random bullets are a fact of life too, so not everyone you duel will be at full health.

That's exactly why when I play BASR infil I don't shy away from body-shots. Chances are that a fair amount of those player I hit won't have full health - and some of those bodyshots will result in kills. This is especially true in hectic CQC fighting - and even more so if you can keep a mental eye on what is going on around you you and predict who might be likley to have recently been in the line of fire.

-Stigma

HA w/ Resist Shield + Conc nades + LMG of choice works pretty effectively if you know roughly where the CQC sniper is. Like if they're holed up in a room somewhere. And unlike the Adren/NMG Shields, Resist Shield gives me 15 seconds of OHK-proof shielding since its EHP doesn't drain over time. It's 1667 EHP until I get shot.

I've also had pretty good luck with LA using either a CQC weapon or a long range carbine (I prefer the Solstice Burst, but Pulsar C works too). If going the CQC route, I'll stay out of sight on a rooftop, using sound to track them down, then I drop down on them from above once I pinpoint their location. If they're indoors I'll try to come in from a doorway behind them. I've not tried leading w/ a flashbang but I'm guessing it would be pretty effective.

Using LA with a long range carbine is more of a cat-and-mouse game, with me hopping from rooftop to rooftop trying to find a good flanking angle to shoot them from, trying not to draw their attention and waiting to shoot until they're busy attacking someone else.

SMF Infil + Emp nade would probably work pretty well too.

But no matter what method I use, I always wait a bit before I make my move. I wait long enough until they either shoot at someone else or their cloak wears out and I hear that decloak noise so I know their general location. I never charge them head on, and I try to stay hidden until I already know where they are to minimize the chance of getting ambushed myself.

Call them out in /region. CQC snipers need unalert enemies to succeed.

Flanking them with a SMG infil works well (or a Stalker). Make sure you dont show up on their radar, deploy mines and a sensor.
If you are comfortable with it, going CQB sniper yourself also works. Wait for them to come to you and get the first shot off.
EMP works well for disorienting them and removing radar.

General advice: As long as you can flank and surprise them they should die easily before they get a chance to kill you.
If you show up on their radar, you are most likely dead no matter what as soon as you step around the corner where they are.

pinpoint his location and just rush him with a group of people in multiple directions , 10/10 requires teammates.

Assuming they have the 2.1x headshot multiplier on them (like most sniper rifles) they would still do 1470 damage on a headshot at max damage.

If you've made the fight into SMG vs Commy at close range then it's very much in your favour. You should win unless there's a big skill gap, or they get lucky.

The other thing that occurred to me if you're good with it is LA (maybe even drifters). As someone else said, unpredictable movement is key to preventing headshots, and LA is the king of that as you've got a whole extra axis to flail around in

Okay. So you made me do math to explain what my eyeballs already know.

I mostly play Vanu, so using Vanu variant names.

Ghost does 700 damage. 700 x 2.1 = 1470 on a headshot at 0-10 meters.
Parsec (Directive sniper rifle, does a bonus 50 damage) does 750 damage. 750 x 2.1 = 1575 on a headshot at 0-10 meters.

Heavy with resist shield gets 40% damage reduction, which means they take 60% damage. I'd explain why that is more than 40% bonus health, but you'd probably think I'm biased. So, as per the wiki:
"Use the following formula: Effective Health = Current Health / 0.60
Ex. If activating Resist Shield at full health: 1000 / 0.60 = 1667 effective health."

So no sniper rifle, even the highest damaging variant, will one-shot a Heavy who starts from full health and has a resist shield. Not even at point blank range.

You are correct, however, on the Nanite Mesh Generator shield. It's 450 HP, so assume you pop it right before you eat a headshot it's only going to give you an effective HP of 1450. You'd need the 700 damage sniper rifle variants to lose about 20 damage before you'd break even in ideal circumstances, and the directive sniper rifle to lose a whopping 125.

Since the Ghost drops from 700 to 400 (delta 300) from 10m to 265m (delta 255) and it's linear, it's pretty easy to map out exactly how far away that is. You'd need to be 27m (17m to lose 20 damage, starting at 10m) from the sniper to survive a headshot with the Ghost with the NMG shield, plus some meters if you've had the shield draining for a second. That still realistically fits an indoor firefight, and I've definitely seen NMG Heavies survive a headshot from my Ghost at those sorts of ranges (though less often than Resist Shield Heavies, which I've shown why up above). It's actually the reason why I use the Parallax even when I'm short range sniping--less damage drop off means fewer Heavies tanking the headshot.

Just for those curious, a summary since I was already doing the math. You can figure it by taking the change in damage divided by the change in distance to get the damage points lost per meter. Find where that equals the HP deficit of the Heavy and add 10 for the 10 meters that no damage drops off. It's a linear change, starting at 10, so it really is as simple as rise over run.

NMG Heavy can theoretically (full health and activates NMG close to the time of the sniper shot) survive a headshot from:
Ghost at 27m or greater.
Parallax at 36m or greater.
Parsec at 122.5m or greater, which makes me want to give it a try for CQC despite the slow fire rate and extra large detection radius.
Bump it up by some fraction of that to allow for a realistic 0.5-2 seconds of the NMG draining (NMG loses 12.5 HP or roughly 3% per second), since you'd usually activate it right before turning the corner into the person you're about to duel.

A Resist Heavy will always survive a headshot from any sniper rifle provided he starts with full health (I hate those guys).

On a good day of cqc sniping, half of my targets don't have the time to respond (at least on my screen) before I drop them. Cqc sniping is OP in most situation.

If you want to counter them, try EMP nades. There is a good chance that the sniper will lose his temper and run away. And smg infil are quite annoying to take out.
Maybe resist sheild in its current state could save you, as you can keep it activated for a very long time now. Dunno.

I guess resist shield was another minor oversight. With my limited time sniping I've never really had a problem with heavies surviving. This is likely due to me not using a typical sniper rifle, I use the Phaseshift.

Even with my minuscule amount of time with the Ghost (and a little with the TSAR-42) I haven't had a heavy survive my shot before.

I also don't know why I'd think you were biased, but whatever. It's not like it's important anyway.

You do know, that Shotguns are a bad choice? They are way too inconsistent to stand a chance against any semi decent player if you dont get behind them or get the drop on them (or RNGesus loves you)

Just because we're on the internet and we were contradicting each other, didn't mean any offense. I actually enjoyed doing that math, I found some surprising things. I'm sort of a number cruncher person and hadn't thought of working out the OHK distances before outside of the generic cases listed in patch notes.

raise the tax on his tampons.

If you can't force him to miss, there's pretty much nothing you can do, besides trying to sneak up on him as a stalker, or flank otherwise.

It's easier to force him to miss if you use a mobile weapon, such as an SMG, and use hip fire.