Why does my gun shoot upwards after the first few shots?

I'm making a gun.

The guns works perfectly other then the fact that the gun shoots up into the air after the first few shots.

I absolutely have no idea why.

It seems to aim up when I hold the trigger down, but if I tap the button slowly it doesn't occur as much.

Here are the important parts of the gun what do the damage and stuff.

LOCAL SCRIPT:

script.Parent.GunShootEvent:FireServer(mouse.Hit.p) --/triggers enemy damage on click or on hold.

SCRIPT:

ShootEvent.OnServerEvent:connect(function(player, aimplace)
    local chr = player.Character
    if script.Parent.Parent == chr then
        if AmmoLeft.Value <= 0 then
            print("No ammo left.")
        else
            if allowedFire then
            allowedFire = false
            GunSound:Play()
            if script.Parent.Staters.Mode.Value == "Semi" then
                MakeBullet(aimplace) --/makes enemy have damage.
                AmmoLeft.Value = AmmoLeft.Value - 1
            elseif script.Parent.Staters.Mode.Value == "Burst" then
                MakeBullet(aimplace) --/makes enemy have damage.
                AmmoLeft.Value = AmmoLeft.Value - 1
                wait(0.05)
                MakeBullet(aimplace) --/makes enemy have damage.
                AmmoLeft.Value = AmmoLeft.Value - 1
                wait(0.05)
            elseif script.Parent.Staters.Mode.Value == "Full" then
                MakeBullet(aimplace) --/makes enemy have damage.
                AmmoLeft.Value = AmmoLeft.Value - 1
            end
            allowedFire = true
        end
        end
    end
end)

=========================================================================

local function MakeBullet(Target)
    local HandlePosition = script.Parent.Handle.CFrame + script.Parent.Handle.CFrame:vectorToWorldSpace(Vector3.new(0,0,.3))
    local TargetLookWay = HandlePosition:vectorToWorldSpace(Vector3.new(0,1,0)) * 200
    local TorsoLookWay = (script.Parent.Parent:FindFirstChild("Torso").CFrame.lookVector * Vector3.new(1,0,1)).unit
    local TargetAngle = (TargetLookWay * Vector3.new(1,0,1)).unit
    local Angle = math.acos(TorsoLookWay:Dot(TargetAngle))

    if math.deg(Angle) < 90 then
        TargetLookWay = Target - script.Parent.Handle.Position
        if TargetLookWay.magnitude > range then
            TargetLookWay = TargetLookWay.unit * range
        end
        TargetLookWay = TargetLookWay * 1.1
    end

    local RayRay = Ray.new(HandlePosition.p, TargetLookWay)
    local NewPart, position = game.Workspace:FindPartOnRay(RayRay, script.Parent.Parent)
    if NewPart and NewPart.Parent and NewPart.Parent:FindFirstChild("Humanoid") then
        if NewPart.Name == "Head" then
            NewPart.Parent:FindFirstChild("Humanoid"):TakeDamage(damage * 1.25)
        elseif NewPart.Name == "Left Arm" or NewPart.Name == "Right Arm" or NewPart.Name == "Left Left" or NewPart.Name == "Right Leg"then
            NewPart.Parent:FindFirstChild("Humanoid"):TakeDamage(damage * 0.9)
        else
            NewPart.Parent:FindFirstChild("Humanoid"):TakeDamage(damage)
        end
    end 

    if position then
        TargetLookWay = position - HandlePosition.p
    end
end

If you need to know anything else, please ask or if you need to see a video of what is happening, just ask me.

Thanks to anyone who helps!