Not exactly an Enfield

Folks,

Not exactly an Enfield but I'm not really sure where else to post this, particularly as this Forum is populated with more than it's fair share of knowledgeable Antipodeans.

Anywhoo the attached belongs to a friend of mine and he'd appreciate any info he can get on the beasty. It's chambered in 577/450 and one side of the action is marked "Henry's Patent" and the other side N A & A Co Ltd 1877.

The cartouche on the butt reads "The National Arms & Ammunition Co Ltd Birmingham 1877". And I assume the other stamps refer to a Military district of New South Wales?

Any help is gratefully received.

Cheers,

Simon.

It is a Henery rifle used by the NSW colonial forces in the 1870's.