400

When I first read his post my thoughts were exactly the same as yours and Marrakai's, I just could post them.

I have seen a early european 470 which is also lightweight compared to English DR's of that period and I own, have owned and handled alot of English Big Bore doubles and none are in that light weight category.

As to an out of sequence number, it is well out and I think more likely a reproof, rebore or rebarrel as you say.

We will have to wait for more photos.

500 Nitro