Thank you to everyone that responded. All responses were very informative and taught me exactly what I wanted to know.
The reason why I wanted to know, is because I have a friend with a .22 Hornet built on a Lee Enfield action - it looks like a miniture .303 and this is what he managed to find out about the rifle:
When NATO switched to the 7.62 after WWII, Brittain apparently declared the use of the .303 unlawful for civil use. This left the factory in Lithgow, Australia with a huge stockpile of .303 barrels(not yet drilled), actions and stocks. To get rid of these parts, Lithgow then adapted it for different calibers, hence the .22 Hornet looking like a Lee Enfield.
I'm not sure if they adapted it for other calibers too and it will be interesting to know if there are more of these rifles out there.