Sledge
L85A2 - ACOG/Flash Hider or Holo/Compensator
SMG-11 - Flash Hider
Thatcher
AR33 - Flash Hider
L85A2 - ACOG/Flash Hider or Holo/Compensator
Smoke
FMG-9 - Flash Hider
SMG-11 - Flash Hider
Mute
MP5K - Compensator
SMG-11 - Flash Hider

Ash
G36C - ACOG/Flash Hider or Holo/Compensator
R4-C - Compensator
Thermite
556XI- Flash Hider
Castle
UMP45 - Compensator
Pulse
UMP45 - Compensator

Twitch
F2 - Muzzle Brake
417 - Muzzle Brake
Doc
MP5 - Flash Hider
P90 - Muzzle Brake
Rook
P90 - Muzzle Brake
MP5 - Flash Hider

Glaz
0Ts-03 - Muzzle Brake
Fuze
6P41 - Flash Hider
AK-12 - ACOG/Flash Hider or Reflex/Compensator
Kapkan
9x19VSN - Compensator
Tachanka
9x19VSN - Compensator

IQ
AUG-A2 - Flash Hider
552 COMMANDO - Flash Hider
G8A1 - Compensator
Jäger
416-C CARBINE - Flash Hider
Bandit
MP7 - Muzzle Brake

Buck
C8-SFW - Muzzle Brake
CAMRS - Muzzle Brake
Frost
9mm C1 - None

Blackbeard
MK17 CQB - Flash Hider
SR-25 - Muzzle Brake
Valkyrie
MPX - Compensator

Capitão
PARA-308 - Flash Hider
M249 - Scope/Flash Hider or Holo/Compensator
Caveira
M12 - Flash Hider

Hibana
TYPE-89 - Flash Hider
BEARING 9 - Flash Hider
Echo
BEARING 9 - Flash Hider

Jackal
C7E - ACOG/Flash Hider or Holo/Compensator
PDW9 - ACOG/Flash Hider or Holo/Compensator
Mira
VECTOR .45 ACP - Flash Hider

Ying
T-95 LSW - Compensator
Lesion
T-5 SMG - Flash Hider

Zofia
LMG-E - Compensator
M762 - ACOG/Flash Hider or Holo/Compensator
Ela
SCORPION EVO 3 A1 - Compensator
F0-12 - Extended Barrel

Dokkaebi
Mk 14 EBR - Muzzle Brake
Vigil
K1A - Flash Hider

Lion
V308 - Flash Hider
417 - Muzzle Brake
Finka
SPEAR .308 - Flash Hider
6P41 - Flash Hider

Maestro
ALDA 5.56 - Compensator
Alibi
MX4 STORM - Compensator

Maverick
AR-15.50 - Muzzle Brake
M4 - Flash Hider
Clash
SPSMG9 - Flash Hider

Nomad
AK-74M - ACOG/Muzzle Brake or Holo/Compensator
ARX200 - Flash Hider
Kaid
AUG A3 - Flash Hider

Gridlock
F90 - Compensator
M249 SAW - Scope/Flash Hider or Holo/Compensator
Mozzie
COMMANDO 9 - Flash Hider
P10 RONI - Compensator

Nøkk
FMG-9 - Flash Hider













Warden
MPX - Compensator

Amaru
G8A1 - Compensator
SMG-11 - Flash Hider












Goyo
VECTOR.45 ACP - Flash Hider

Kali - N/A
Wamai
AUG A2 - Flash Hider
MP5K - Flash Hider

Iana
ARX200 - Flash Hider
G36C - ACOG/Flash Hider or Holo/Compensator
















Oryx
MP5 - Flash Hider

Ace
AK-12 - ACOG/Flash Hider or Reflex/Compensator













Melusi
T-5 SMG - Flash Hider

Definitions:
Muzzle Climb (vertical recoil): How much the weapon kicks upwards when fired.
Stability (horizontal recoil): How much and how often the weapon kicks to the left and right.

Barrel Attachments:
Muzzle Brake: Reduces first shot recoil by 45% and centering time by 45%. Results in tight 2-3 shot bursts and allows for less time between bursts. No effect on stability.

Flash Hider: Reduces first shot recoil by 37.5%, reduces centering time by 30%, and improves stability by 5%. Contrary to common belief it doesn't remove the white indicator that shows up on your opponent's screen that shows which direction you're firing from or hide your bullet trails. However, it diverts the muzzle flash of your weapon sideways so you can still see your target when you shoot. It's not always the best choice but it's never a bad one either.

Compensator: No effect on muzzle climb but improves stability by 17.75%. Resulting in more vertical kick but a narrower and more predictable recoil pattern. Useful on weapons that have low muzzle climb and/or poor stability.

Suppressor: Reduces noise made by your weapon, hides your bullet trails, and removes indicators on your opponent's screen that show where you're firing from. They have 0 recoil benefits and reduce weapon damage. Recoil changes made in Grim Sky made lack of recoil mitigation less of a deal breaker than before. The suppressor is a viable weapon attachment but not that much better than using a muzzle brake, flash hider, or compensator. Unpredictable recoil and lower damage means fewer hits and also needing more hits to kill.

Extended Barrel Borderline useless. For a full explanation see Rogue 9's YouTube video The only weapon this should be used with is Ela's FO12 shotgun.

Grips : The vertical grip reduces recoil. The angled grip improves aiming speed. The angled grip is situational and generally shouldn't be used. Most of the time you'll already be aiming when the fight starts making the angled grip useless in the majority of firefights. The vertical grip helps in every firefight and is the better choice by far. The vertical grip is going to be the better option for 99% of players. The only weapon that the angled grip is the best choice for is the BOSG.12.2, as recoil isn't a factor when the practical rate of fire is that slow.

Sights (Largely personal preference): There are plays you can make with a Holo or Reflex sight that you can't make with an ACOG and vice-versa. For someone with a more fast paced play style a Holo or Reflex would be optimal. If you're more patient and methodical then the ACOG will benefit you the most when holding angles and in medium-long range fights. The only "bad" choice is the Red Dot, as it's inferior to Reflex in every way.

♥♥♥♥♥♥' Laser Sights: Reduces hip fire spread by 25%. Laser sights shouldn't generally be used as they can give your position away to opponents and the red glare of the sight can make it easier to see you. However, some weapons are worth putting a laser sight on; All shotguns except the BOSG.12.2 (To help with weapon spread). Jackal's PDW9 (Makes hip fire spread so tight that you can use ACOG for medium-long range fights and hip fire for close range engagements). Shield ops should always use a laser sight on pistols as they rely heavily on hip fire.

Here's the link to Cynibot's original post: Link

Here's the link to Rogue 9's Youtube Channel: Link

Here's the link to the Rainbow Six Siege Wiki (Where I got the Images): Link[rainbowsix.fandom.com]

Latest Update (8/1/2020):

• Changed the title of the guide
  
• Included which season each section is from
  
• Added 3 new sections for Y4S4, Y5S1, Y5S1
  
• Added some sight recommendations
  
• Changed recommendations for:
  
• L85A2
  
• G36C
  
• F2
  
• AK-12
  
• MP7
  
• C8-SFW
  
• M249
  
• C7E
  
• PDW9
  
• VECTOR.45 ACP
  
• T-5 SMG
  
• M762
  
• K1A
  
• V308
  
• ALDA 5.56
  
• AK-74M
  
• F90
  
• M249 SAW
  
• Commando 9