How Do I Script/Fix Manofthelols guns?

Hi, There to anyone who is reading this if you know manofthelol he makes these old fps guns which broke due to the roblox scripts update and etc, when i realised these guns had broke i had a attempt to fix them and only one gun that i fixed works a M4A1 Heres the script to it and it works fully but when i tried to convert it to the other manofthelols guns it does not work and the bullets travel far away from me and doesnt hit the target at all! please check the bullet script as i tried a attempt to fix it

Bullet Script

ball = script.Parent
damage = math.random(10,20)
local hitt = false

HitSound = Instance.new("Sound")
HitSound.Name = "HitSound"
HitSound.SoundId = "http://www.roblox.com/asset/?id=11945266"
HitSound.Pitch = .8
HitSound.Volume = 1
HitSound.Parent = ball

function onTouched(hit)
	if hit.Parent:findFirstChild("ForceField") ~= nil then return end
	if hit.CanCollide == false and hit.Parent:findFirstChild("Humanoid") == nil then return end
	if hit.Parent.className == "Hat" and hitt == false then
		hitt = true
		hit:BreakJoints()
		hit.Velocity = ball.Velocity
		hit.Parent.Parent = game.Workspace
	end

	if hit:findFirstChild("Metal") ~= nil and hitt == false then
		hitt = true
		for i = 1,math.random(1,3) do
			local j = Instance.new("Part")
			j.formFactor = "Plate"
			j.Size = Vector3.new(1,.4,1)
			j.BrickColor = BrickColor.new("Bright yellow")
			j.CanCollide = false
			j.Velocity = Vector3.new(math.random(-10,10),math.random(-10,10),math.random(-10,10))
			j.CFrame = script.Parent.CFrame
			j.Parent = game.Workspace
		end
	end

	local humanoid = hit.Parent:findFirstChild("Humanoid")

	if humanoid ~= nil and hitt == false then
		hitt = true
		tagHumanoid(humanoid)
		if hit.Name == "Head" then
			humanoid.Health = humanoid.Health - damage * 2
		elseif hit.Name == "Torso" then
			humanoid.Health = humanoid.Health - damage * 1.5
		else
			humanoid.Health = humanoid.Health - damage
		end
		wait(.2)
		untagHumanoid(humanoid)
	end
	if hitt == true then
		HitSound:play()
		ball.Parent = nil
	end
end

function tagHumanoid(humanoid)
	-- todo: make tag expire
	local tag = ball:findFirstChild("creator")
	if tag ~= nil then
		local new_tag = tag:clone()
		new_tag.Parent = humanoid
	end
end


function untagHumanoid(humanoid)
	if humanoid ~= nil then
		local tag = humanoid:GetChildren()

		for i = 1, #tag do

			if tag[i].Name == "creator" then
			tag[i]:remove()
			end
		
		end
	end
end

connection = ball.Touched:connect(onTouched)

while true do
wait(.01)
if damage < 0 then
break
else
damage = damage - .2
end
end

ball.Parent = nil