.
Thetford CGR/ ETR are non HME ranges with a maximum energy limit of 4500 joules. The RSOs permit calibres up to 308/7.62 including .303 and have been in effect for a number of years. One Landmarc range warden has previously indicated ..303 was excluded under the RSOs but that was quickly resolved.
Barton Road Is a 7000 joule HME range. The RSOs do not have a calibre limit other than specifically prohibiting the civilian use of 338. 7.92mm may be used on this range, i will caveat this by saying I have not run Barton as a RCO for a few months, but I have not had seen any revised RSOs which revise the above.