My shrunken thrower isn't working? I cant seem to make it go forward

When I use this it spawns on me but it keeps moving left and right repeating (this is in the projectile) What I'm trying to do is make projectiles that launch forward/where im looking, it goes forward for 4 seconds but it isnt working

local Prop = script.Parent
local plr = game.Players.LocalPlayer
local MyBody = plr.Character
local mouse = plr:GetMouse()
local MyTorso = MyBody.Torso

while true do
    wait(0.5)
    Prop.CFrame = MyTorso.CFrame + (CFrame.new(Prop.Position, MyTorso.Position).lookVector * 4) + Vector3.new(1, 0, 0)
end