Amongst the features planned for version 1.2 is the ability to add scope and silencer attachments to guns.
There are two types of scope: scout and sniper. Both increase accuracy and visual range, however the sniper scope gives more accuracy and more visual range. Only rifles can accept scope attachments.
Silencers can come in 9mm and 5.56mm caliber versions. Only certain guns can accept silencers. Silencers can be changed during the battle (unlike scopes). Shooting a weapon with silencer will not alert the enemy to your whereabouts, but reduces the power of the gun by 10%.
Both scopes and silencers are obtained by purchasing in arms dealer, or more likely dropped by enemy soldiers.