If your talking about fore grip pretty much its useless almost every gun you are able to handle without you losing control of.
Sets most people say need grip: Submachine, Light machine guns and Assault rifles.
I mean sub machine guns if you have used each gun you will notice some you are not able to take control when aiming, it loses control.
As for assault the only one I know you need grip would be AN-94.
Light machine guns I dont know if its just me but I always lose control but either way to make it more understandable if your shooting the enemy from a close range then you wont need fore grip. If you are trying to shoot from a medium or long range prepare to not be able to handle the gun.
If your wondering how I know Ive had almost all sets diamond except the shield and launcher set.
My K/D is not awful its 2.05
Attachments... lol I hardly care if I cant control it I just make sure I kill the enemy so in all my guns I only use fast mag.
Just make sure when you use the set do not expect that youll have control if your trying to shoot from a medium or long range.
The only gun that I use it on is the FAL.. I put select fire, grip and sometimes stock.. Makes it a lot better for me.. On the AN 94, I only use the stock and fast mag or extended mag.. The stock helps move so much quicker and I burst fire it while doing so, and never have many problems.. I've never seen any need in using the grip on any smg, other than maybe the scorpion.. That gun is just stupid fast, but another where burst fire really helps.. But that's just me..
Best stick the laser sight on the skorpion and hip fire. Again , its fine to ads tho in HC as a couple of hits kill.
I did fine with the FAL and select fire without grip, I prefer the M8A1 in normal mode. The SMR is somewhere inbetween, even with the select fire the fire rate is quite slow and I feel you need great aim, its also one of the few guns I like the suppressor on as the noise irks me, like the Chicom.
All the stats and vids in the early days suggested that Grip is uselss apart from 1-2, the one it had most effect on was the Scar, and that difference was small, the Scar recoil goes upwards as oppose to most guns that go to the side, so it helps with that. The other was the MK48 I think, but cant remember. I have no idea how it effects the peacekeeper.
The only attachment you really must have is stock on ARs, unless you camp, and even then the move time when ads is so slow its horrendous. I cant use ARs without stock, it feels like an LMG without it. Then I prefer blue dot on ARs apart from the Scar coz the gun looks ugly with the dot. The rest is personal preference, but every other attachment has it uses. You can get away with 2 on all ARs apart from the Type 25 which has very slow reload, very bad iron sights, very slow raising gun time, and a few other drawbacks. It makes up for that by having the fastest fire rate, hence its a noobs gun imvho, its like a hybrid smg/ar, its shocking at distance as it has crazy recoil, but hip sprayers love the gun. When I use it, I have to have 3 attachments.
The SMGs are simple, you need quickdraw and fast mags if your a runner, if your a bit laid back go with long barrel inplace of 1 of those or maybe drop both and add suppressor. The pdw doesnt need fast mags due to the extra ammo but if like me you reload after every kill anyway, it makes no difference. If you have a slow trigger finger, you automatic fire on the chicom, with fast mags and red dot, as it has awful iron sights. Infact the chicom reminds of the type 25, it could use about 5 attachments and has decent range so is almost a smg/ar hybrid.
If you play core you NEED toughness on all guns as the flinch is huge. Lightweight is so good and makes you harder to hit, thats another must in any mode. Same with dexterity in 3.
If you play HC however, like I do, theres things you dont need, and things you deffo do need. You dont need toughness as the killtime is instant, so change that out for cold blooded if you hit a target finder lobby, or run scavenger if not. Scav also helps as you need engineer as theres a vast amount of equipment in HC, and this is where you need EMPS, scav replaces them and you can get huge xp on equipment kills alone, also no secondary needed as you never run out of ammo.
Fav HC class AR
M8A1 + stock + blue dot
dexterity + engineer
Fav HC class SMG
MSMC + quickdraw + long barrel
dexterity + engineer
Dependent on the lobby your in, you can change 1 emp for a fhj launcher, or scav to cold blooded to counter the opponents, but the rest are musts imvho
Shotguns are useless on my connection, LMGs are far too slow coz I like to move, and I cant snipe for ****. Ive over 200`000 kills in this game on 2 platforms and have master prestiged 3 times, so know my onions about the guns in question and ive tried pretty much everything going.
PS regarding streaks, care packages are great in HC especially as your using engineer and can change the contents, BUT the scumbags who kill you and steal your package put me off. Escort drone can do serious damage, but I go for uav/hunter killer and lightning strike, the strike can get 4-5 kills against a spawn camping team, the splatter damage and low health of players makes a huge difference.
Just my opinion
Hope it helps