New olives too thin?

[copea]

Evening,

I wonder if someone can help with this very basic problem I'm having please?
I've just re-piped up to a PRV and I've gone to replace the section of pipe with the old olive on.
The old one seems to be much thicker/taller than the any of the new ones I have, meaning that when I put a new olive on (numerous brands of copper and brass) and tighten the nut, it doesn't grip the pipe. I can slide it off even after tightening up the nut as far as it will go.

Any ideas? Special kind of olive perhaps?
Stupidity on my part? Any suggestions welcome.

I've uploaded a photo of the old one, which has a dip/valley running through the middle of it, unlike any of my new ones.

Thanks!
Andy

 

[Burnerman]

Maybe the original pipe was the old 1/2”......normally compatible enough, especially when a copper olive is used.
I remember these grooved olives were specially used to convert 3/4” to 22mm - and they often had a green varnish applied so you knew what they were.
John