Random movement and shaking-

I am making a gun for a project. Everything works, except for the ADS system. Basically, it goes crazy at complete random a lot of the time and im unsure why. The gun just shakes and also moves the character. Here is the code below, with a video showing what I mean:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local render = game:GetService("RunService")
local body = script.Parent.Body
local uis = game:GetService("UserInputService")
local cam = workspace.CurrentCamera
	cam.CFrame = cam.CFrame:Lerp(CFrame.new(cam.CFrame.p, mouse.hit.p), .2)
	body.CFrame = body.CFrame:Lerp(CFrame.lookAt(script.Parent.Body.Position, mouse.Hit.p),.6)

The rapid camera movement in the video is not what I mean, I mean the shaking of the gun before and after that.