I didn't make it!
I was wondering if anyone could tell me which game or gametype or whatever it is where you can use mp5, i have every version of it but i dont know how to use mp5. thanks for help.
you would need to join a server that has this weapon enabled. after doing so select it from the outfitting screen.
Also, if you have version 1.00, you're SOL. Update to 1.03 and then you'll be able to use the gun.