I had a BIG argument with out local Police 'Manager of Firearms Licensing'.
In the UKthe Police authorise the ground you can shoot over and rate it up to certain calibres - they approved my land for up to 303.
When I applied for a L42 in 7.62 / 308 they refused as they said my land was not approved for above 303.
It took some arguing that 303 and 308 were measured differently, with 303 being the 'bore' diameter and the 308 was to the bottom of the rifling grooves - when comparing like-for-like the 303 was actually 312, ie bigger than 308.
Case proven - I got my authorisation to buy a 308.
After that they actually gave me an 'open licence' so I didn't have to go thru it all again - I could shoot on any land with any calibre that (I was licensed for) that I deemed safe.
No more Police vetting.
The Police then altered their central calibre lists to show 303 as 303/7.7, much as they already show 308/7.62