Why my Fireball script don't work? Help me, beacouse idk what to do

rs = game:GetService("ReplicatedStorage")
ss = game:GetService("ServerStorage")
local tweenservice = game:GetService("TweenService")

rs.RemoteEvents.FireAnigilation.OnServerEvent:Connect(function(player, Mouse) 
	local char = player.Character
	local hum = char:WaitForChild("Humanoid")
	local pposX = char.UpperTorso.Position.X
	local pposY = char.UpperTorso.Position.Y
	local pposZ = char.UpperTorso.Position.Z
	print(pposX,pposY,pposZ)
	pposY = pposY + 10
	local core = rs.FireAnigilation.core:Clone()
	core.Parent = workspace
	core.Position = Vector3.new(pposX,pposY,pposZ)
	local velocity = Instance.new("BodyVelocity", core)
	velocity.MaxForce = Vector3.new(5000,5000,5000)
	velocity.Velocity = CFrame.new(core.Position, Mouse).LookVector * 100
end)

WHYYYY? When ball is small, fireball is working but when fireball is big, he doesn't work(((

MaxForce was low))))