Right arm following mouse in a weapon?

I'm trying to make a gun where your right arm follows your mouse when it's equipped. Here's what I have:

player = game.Players.LocalPlayer
repeat wait() until player.Character
char = player.Character
shoulder = char.Torso["Right Shoulder"]
original = shoulder.C0
active = false

function onEquipped(mouse)
    active = true

    while active == true do
        shoulder.C0 = CFrame.new(shoulder.C0.p, mouse.Hit.p)
        wait()
    end
end

script.Parent.Equipped:connect(onEquipped)

script.Parent.Unequipped:connect(function()
    active = false
    shoulder.C0 = original
end)

When I try to aim forward, my arm is facing to the right of me. When I aim right, my arm points behind me. Any ideas on how I'd fix this?