As it stands at the moment I’m not sure what type of rifle I’d like. What is the best way of filling out the form so that I have the option between the two after the certificate is granted? Or is it the calibre that is sanctioned irrespective of the action?
You are correct in thinking that you apply for a rifle by calibre and not by action type, so if are granted authority to acquire a .308 or a .30-06 you can buy whichever action type you decide upon.
Which brings us rather neatly to the differences between calibre bullet diameter and cartridge designation.
Calibre is the diameter of the bore before the rifling is cut and that dimension may or may not appear in the name of the cartridge.
Thus, the .308 Winchester is not a calibre, it is a cartridge; .308 is the bullet diameter, because jacketed bullets are made to the size of the bore after it is rifled, and the calibre is .30 or .300.
Similarly, .30-06 is not a calibre, it is a cartridge whose calibre is .30 or .300.
All this pedantry, however, gets us absolutely nowhere when dealing with bureaucracy.
We must be a bit flexible.
The Firearms Acts talk about calibre and that is the word used on the application form for your certificate but if you treat it literally the police don’t know whether you want a .30-30 or a .30- 378 Weatherby Magnum.
Likewise, the dealer from whom you want to buy ammunition will not be certain he can sell you what you ask for if your certificate simply allows 200 rounds of .30 calibre.
You can’t expect politicians to get it right which means that we and the police have to sort it out between us!