Cricket 25 outside barrel diameter ??

Hi guys
Just planning a future conversion ,could someone please tell me the outside diameter of a 25 cricket barrel please? In metric if.poss ,ive gone all.europeanified !! Conversion is going to be be a lothar walther blank in 30 cal,,any other info regarding the conversion port diameters etc would be appreciated !! Its going to be unchoked looking at shootins slugs as well.as pellets
Thanks
Rgds steve