It is the most reliable and flexible weapon in the game. The mix of accuracy, power, fire rate, and mobility means you can use it at any range with good results.
Best Sniper Rifle - AX-50
This will give you a one-hit kill if you take a good enough shot, and it is more mobile than most of its competitors. Sniping is all about moving around and hiding, so this fits the bill perfectly.
Best Marksman Rifle - KAR98K
Marksman rifles feel a bit like a diet sniper rifle, but with the right upgrades the KAR98K can get the job done just right. It's got an obscene range, damage, and accuracy and you don't lose mobility either.
Tactical rifles are new to Warzone and they offer a different experience to the assault rifles because they fire in bursts and the M16 has an insane damage per hit and accuracy over long distances.
Best Tactical Rifle - M16
Best Shotgun - R9-0
This gun will make you feel like a total badass just in case you want to indulge yourself in some close combat. Dragon's Breath Rounds attachment will help you massively with it.
Best SMG - MP5
This gun is a tonne of fun if you've just started playing the game. It has a high firing rate, good accuracy and lets you run around like crazy.
Best LMG - Stoner 63
This gun has an obnoxiously high damage output and fire rate in the game. The recoil pattern is a bit difficult to get used to and it does weigh you down a bit while moving.
Best Launcher - JOKR
JOKR is good for just one thing in the game — taking down vehicles. It also has lock-in, so it will follow around the target till it's completely obliterated.