Have no fear, I am going to try and break down the differences between all of the attachments and help the learning curve, whether for new players or players simply trying to rank up, get easier. Outside of the ACOG, the sights seem to be almost exactly the same with slight cosmetic differences, all of the barrel attachment descriptions can start to read similarly after a while, and things like laser sights, silencers, and extended barrels seem to have very little drawbacks and a lot of benefits.
Rainbow Six Siege is many things, it is a hardcore First Person Shooter that requires a lot of forethought, strategy and gun skill to play at higher levels, it is a fun game that tests even experienced players, and it is also a game that can seem overwhelming when it comes down to choosing which operators, which weapons, and which attachments you want to use.