Here's the yarn again, for those interested:

Greener Empire Conversion

...and a couple more successful hunts with that double:

Back-pack Hunt with the Missus

Pig and Pussy Hunt!

Needs a bit more editing, but I consolidated my thoughts on the .577 Light Nitro cartridge as a conversion candidate (modified from a previous post):

.577 x 2 3/4 Nitro Express

Hope this is of some interest.