I went looking for a genuine Siamese Mauser extractor. I found one, it cost me AU$200 delivered,but it came with other bits.
This not a virgin action. It has been converted for 45/70 at some stage. A new bolt handle welded on (a bit rough), the bolt face opened up and the right hand feed rail opened up to help feed for the larger rim. It feeds 348Win cases perfectly.
The case above is a 348W that did not quite fire form fully for the 416/348W AI. Not enough pressure generated during forming. It only formed where the brass was annealed.
The rear scope mount is not the prettiest work I have seen and it is alloy - it will need some extra work and hopefully a change to a Leupold base.
I bought the action sight unseen. Before it arrived I was thinking 338WSM, but as the feed rails and bolt face has been openned more than standard that is now not an option. But I can use a 338WSM reamer (which I can rent) and headspace the chamber. While it is in the lathe, cut a grove to accept a rimmed case. So it would end up being a 338/348Win Improved. It would not be an Ackley Improved as the shoulder angle would be 35deg not 40deg.
Or I could go the other way and just do a 450 Alaskan.
The Auctioneer's Promise stock finish compound should be delivered this week, so focus will be back on the 416WSM.