The DKS-501 is a fully moddable and high-res retexed Sniper Rifle for Fallout New Vegas, you can attach and detach Carbon Fiber Parts to decrease the weight and also add a Silencer.
The weapon is on a table in Boone’s room in Novac, you have to steal it from him when he is on duty at night. When the rifle is added to your inventory you will get a config item added to the Apparel tab in the pipboy where you can attach and detach the sniper modkits, provided you have any.
The damage done by this weapon is slightly higher then the vanilla sniper to compensate for the missing bonus critical chance the normal sniper has. The crit multiplier is significantly higher when the weapon is silenced. Weapon health is also higher then normal, this is a pretty durable weapon, however it does degrade if you use it often, so maintain it well.