What type of valve connection is on my CO2 tank

[Technobob]

Mystery solved the valve is a CGA 320 as Da Pneu Kid suspected it was

The new adapter fits like a glove Thanks everyone for your help

Now I just need to buy my fittings and I'm good to go well that is when I can afford them I can't believe what they charge for a 4" SCH80 end cap $40 Canadian I'm looking at about $125 in fittings OUCH!!!

So much for a free cannon but I guess the old saying is true "if you want to play you got to pay"