How can i connect my regulator to this valve?

[BlueWhisper]

Its a bs 341 no 3, british standard.

Both if them are 5/8 " threads from what i read, and it screws right in, but it stops a few threads short ( as you can see in the pics)

I tested it and the regulator works but im experiencing pretty massive leaks and sharp hisses .

From looking into it i need a bullring end for this valve i think? Is there any adapter that for that?
Or do i just need to screw it further in with a wrench?

 

[DogDiver]

You cannot. That’s an scba valve. For firemen.

 

[BlueWhisper]

You cannot. That’s an scba valve. For firemen.

Is there nothing i can do about it?

 

[Doby45]

Is there nothing i can do about it?

You can buy a SCUBA regulator. They are two different things.