How do I make a cannonball always shoot in the direction of the muzzle?

Recently, I've been learning how to script, and so I decided to make a simple cannon that fires whenever you press a trigger block. The problem is, I want the velocity of the cannonball that it launches to always be towards the direction of the muzzle. How do I go about doing this? Or is there a more efficient method?

gun = game.Workspace.Cannon
trigger = game.Workspace.Trigger

db = false
function fire()
	if gun == nil then return end
	if db == false then
		db = true

	local projectile = Instance.new("Part")

	trigger.BrickColor = BrickColor.new(1004)

	projectile.Position = gun.Position
	projectile.BrickColor = BrickColor.new(1003)
	projectile.Shape = "Ball"
	projectile.Size = Vector3.new(3,3,3)
	projectile.Material = "Metal"
	projectile.Name = "Cannonball"
	projectile.CanCollide = false
	projectile.Velocity = ???

	projectile.Parent = game.Workspace

	wait(5)
	trigger.BrickColor = BrickColor.new(1020)
	
	db = false
	end
end

script.Parent.Touched:connect(fire)