What do i use to get i bullet to go straight? BodyForce exc

Is this the right way to use it?

function onKeyPress(inputObject, gameProcessedEvent)
	if inputObject.KeyCode == Enum.KeyCode.F then
	local mouse = game.Players.LocalPlayer:GetMouse()
	local gun = workspace.Turret.Gun2
	local gunPos= gun.Position
	local part = Instance.new("Part",workspace)
    part.Size = Vector3.new(1,1,2)
    part.Material = "SmoothPlastic"
    part.Position = gunPos
	part.CanCollide = false
--Workspace
--  Part1
--  Vector3Value

--I am using a Vector3 Value named "Vector3Value" (the object type) to not interfere in the current Velocity
local Force = 1
local Gravity = 1 --The Current Gravity of the Bullet 0-1  |0|None  |.5|medium |1|Full
local PreVelocity = game.Workspace.Vector3Value
PreVelocity.Value = Vector3.new(part.CFrame.LookVector * Force)
part.Velocity = Vector3.new(PreVelocity.Value.X,part.Velocity.Y*Gravity,PreVelocity.Value.Z)

    part.Touched:connect(function(hit)
    if hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid") then
        hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - 3000
	end
    end)
    end	
		
		
		
		
		
		
end

game:GetService("UserInputService").InputBegan:connect(onKeyPress)