Alex, the gun weighs just an ounce or two under 17lb. The twist is 1:100 which should be good for 1.45" long bullets in this diameter per Greenhill's formula and is marked "Kynoch's drawn case for conical ball."

If you decide to go forward with your 4-bore project I'd be glad to send whatever close up part photos or measurements you want if it could assist. I think it would be great if a few more of these guns were built! There are a few folks here in AK with 4 and 8 rifles and shotguns of various action types from Jones UL to TL hammerless that I'm sure I could get detailed info on if it might spur some ideas. Also, my friend Cal Pappas has a book at the publishers right now on British bore rifles that has lots of excellent photos of big guns. It should be out in a few months.

Bob