To me, the Protoype is more of a Marksman's Tool rather than a Sniper's Tool(and before any of you guys try to correct me, try searching it up
).
The Protoype is Decent from Short To Medium Range. It pretty much depends on how fast you can aim and press the shoot button. Essentially, this gun needs a person with a fast reaction time to be really skillful to use it.
This gun usually requires boots with Double Jump(So in case your crosshairs don't find your targets head, you can press jump again and try to align it as close as possible. Also, it's good for trying to dodge a person aiming at you with a sniper); Sniper Boots work great for it as well. For the capes, it's also the Sniper Cape for extra headshot damage.
You're only choice of action in the field with a Prototype is to Run > Aim > Shoot.
Keep in mind when you're running, you are recommended to switch to a Melee after you shoot.
Extra Tip:
Don't bother with it's scope and aim for the head as much as possible.
Disclaimer:
The person you shot at will attempt to kill themselves before you can shoot another round. So
make each of your shots count and aim for the head.