How do i make my Viewmodel module lag free?

I used RunService.RenderStepped because that's the lag free thing i know

My problem is at line 106

Here is the script

local plr = game.Players.LocalPlayer
local mouse = plr:getMouse()
repeat wait(.2) until plr.Character
local char = plr.Character
char:WaitForChild("Humanoid")
local function loadprint(module)
	print(module.." Loaded")
end


--Viewmodel Module
local guns = game.ReplicatedStorage:WaitForChild("Guns")
local viewmodelGun
local diemaus = game.Players.LocalPlayer:getMouse()

diemaus.Icon = "http://www.roblox.com/asset/?id=98386546"
--local animationContent = game:GetService("KeyframeSequenceProvider"):RegisterKeyframeSequence(game.ReplicatedStorage.TestShot)
--script.Animation.AnimationId = animationContent

--game.Workspace.CurrentCamera.CameraType = Enum.CameraType.Scriptable

local offset = Vector3.new(0, -.8 ,0.1)
local modeloffset = CFrame.new(0, -.8 ,0.1)
--[[local function SetViewmodelOffset(vector)
	if viewmodelGun then
		--viewmodelGun:SetPrimaryPartCFrame(cframe or game.Workspace.CurrentCamera.CoordinateFrame)
		offset = vector or Vector3.new(0,0,0)	
	end
end]]

local function scan_nocollide(object)
	local obj = object or viewmodelGun
	if obj == nil then return end
	for _,v in pairs(obj:GetChildren()) do
		if v:IsA("BasePart") then
			v.CanCollide = false
		end
		if #v:GetChildren() > 0 then
			scan_nocollide(v)
		end
	end
end

local function ShowWeaponOnScreen(weapon)
	if guns:FindFirstChild(tostring(weapon)) then
		if viewmodelGun then
			viewmodelGun:Destroy()
			viewmodelGun = nil
		end
		if game.Workspace.CurrentCamera:FindFirstChild("Viewmodel") then -- Somehow a second viewmodel was being created when this was called twice, we just see if we created the viewmodel already and if that is the case we destroy the object.
			game.Workspace.CurrentCamera:FindFirstChild("Viewmodel"):Destroy()
			viewmodelGun = nil
		end
		viewmodelGun = guns:FindFirstChild(tostring(weapon)).Model:Clone()
		viewmodelGun.Name = "Viewmodel"
		viewmodelGun.Parent = game.Workspace.CurrentCamera
		scan_nocollide()
	end
end

script.ShowWeaponOnScreen.OnInvoke = ShowWeaponOnScreen



--[[
	print(game.Players.Player1.PlayerGui.ScreenGui.Viewmodel.PlayParticleOnPart:Invoke("MuzzleFlash", game.ReplicatedStorage.Guns.AK47.Resources.Particles.MuzzleFlash, function (name, icle) 
		wait(0.1) 
		icle.Enabled = false
		print("Disable Particle")
	end))
--]]

script.SetViewmodelOffset.OnInvoke = SetViewmodelOffset
script.PlayParticleOnPart.OnInvoke = function (partName, particle, callback)
	if not viewmodelGun then return end
	local icle = particle:Clone()
	icle.Parent = viewmodelGun:FindFirstChild(tostring(partName))
	icle.Enabled = true
	if type(callback) == "function" then
		coroutine.wrap(function ()
			callback(partName, icle)
		end)()
	end
	return icle
end

local delta = 0
local ti, prevTick = tick(), tick()

--SetViewmodelOffset(Vector3.new(1, -0.75, 1.5))
--SetViewmodelOffset(Vector3.new(1,-1.35,-3))

local oldviewmodelCFrame

local function GetViewmodelCFrame()
	if oldviewmodelCFrame then
		return oldviewmodelCFrame:lerp(game.Workspace.CurrentCamera.CoordinateFrame * CFrame.new(offset), 0.35)
	else
		return game.Workspace.CurrentCamera.CoordinateFrame * CFrame.new(offset)
	end
end
local RunSrv = game:GetService("RunService")

	

RunSrv.RenderStepped:Connect(function()
	if viewmodelGun then
	ti = tick()
	delta = ti - prevTick
	local viewCFrame = GetViewmodelCFrame()
	viewmodelGun:SetPrimaryPartCFrame(viewCFrame  * modeloffset)
	oldviewmodelCFrame = viewmodelGun:GetPrimaryPartCFrame()
prevTick = tick()
end
end)

local function FlickView(vector)
	local cframe = game.Workspace.CurrentCamera.CoordinateFrame * CFrame.Angles(math.rad(vector.x), math.rad(vector.y), math.rad(vector.z))
	game.Workspace.CurrentCamera.CoordinateFrame = cframe
	return game.Workspace.CurrentCamera.CoordinateFrame
end


loadprint("Viewmodel")