Why does this teleport around me when I try to angle it?

I'm trying to make a gun, and I've decided making fake arms is the best way to animate it. I've created the fake arms, but whenever I try to angle them, it sets the rotation to what I would think it's supposed to set it to, but it then teleports it around my character. Does anyone know why this is happening and wouldn't care to explain?

Here's my script for making the fake arms (yes, this is a localscript)

local player = game:GetService("Players").LocalPlayer
local character = player.CharacterAdded:wait()
local rightArm,leftArm = character:WaitForChild("Right Arm"),character:WaitForChild("Left Arm")
local rightWeld,leftWeld = Instance.new("Weld",character:WaitForChild("Torso")),Instance.new("Weld",character:WaitForChild("Torso"))
local fakeArms = Instance.new("Model",character)
local fakeRightArm,fakeLeftArm = Instance.new("Part",fakeArms),Instance.new("Part",fakeArms)
fakeArms.Name = "fakeArms"
rightWeld.Name = "rightWeld"
fakeRightArm.Size = rightArm.Size
fakeRightArm.CFrame = rightArm.CFrame
fakeRightArm.CanCollide = false
rightWeld.C0 = character:WaitForChild("Torso").CFrame:inverse()
rightWeld.Part0 = character:WaitForChild("Torso")
rightWeld.C1 = fakeRightArm.CFrame:inverse()
rightWeld.Part1 = fakeRightArm
leftWeld.Name = "leftWeld"
fakeLeftArm.Size = leftArm.Size
fakeLeftArm.CFrame = leftArm.CFrame
fakeLeftArm.CanCollide = false
leftWeld.C0 = character:WaitForChild("Torso").CFrame:inverse()
leftWeld.Part0 = character:WaitForChild("Torso")
leftWeld.C1 = fakeLeftArm.CFrame:inverse()
leftWeld.Part1 = fakeLeftArm

Here's the script that I've tried to angle the arms workspace.Player1.Torso.leftWeld.C0 = workspace.Player1.Torso.leftWeld.C0 * CFrame.Angles(1,0,0)

Thanks to anyone that can help :)!