To answer the above two posts:
is the standard the standard just because it's always been the standard, or because it's actually the level of work required?
when has a UK AFO ever run out of rounds? If the answer is never, why are you even considering it as a policy driver? If they have, different size guns can use the same rounds. My wife didn't carry an SA80 on ops, but instead was issued a SA80 carbine as it was safer and more effective for her (and those around her).