Bob's right about making sure you are safe with all your fittings, hoses and regulators but another question you should be asking is, "Where am I going to get such a tank filled?" I doubt paintball shops will fill an N2 or Ar tank with hpa. What were your plans on filling?For another option, you might check out the local cost of renting and filling that nitrogen tank with nitrogen. A lot of guys on here use nitrogen and report great results. Just some thoughts.joe