You need to do your homework on this now anyone considering going for a cf calibre needs to write a very consise letter detailing your reasons and rights to own said calibre, make sure your letter contains no negative points as these will be used against you, make it clear in your application that you meet the requirements to own the calibre and have genuine reason to posses, police forces are now commonly quoting " Our forces policy".
This is usually not the actual law just what they want, make sure you are a member of eg. basc, ca, SACS. Liase with your feo and most important of all keep ca