This rifle has been discussed quite a bit before on this site. It is a screw grip type action but is apparently off face and in need of a restock. I think someone mentioned the bores weren't very good either. Do a search.

There are a couple of 450-400 on Champlins that may be worth a call.

As far as weight. My double weighs roughly the same. Would I like it to be a bit lighter, probably. But in a well balanced rifle I really dont notice it that much. Most of the brit 450-400's I have seen have been over 10 pounds it seems. The four currently listed on the Champlins site are between 10 pounds 3 ounces and 10 pounds 14 ounces.

Good Luck with your search.