How about necking 9,3x74R up to .416 bullet ? It might be .416 x 72R. I think it could be good for example VALMET 412 doubles and RUGER 1 singles...

You would have about the same thing as the 405 Winchester.

Could be. Here in europe 9,3x74R components are quite cheap and easy to buy.

Necking up top 416 might be possible, but it would remove most all the taper in the x74 case.

In order to get as much velocity as possible with the heavier 416 bullets, you culd long throat a single shot or double rifle and seat the bullet shallow. I would want a crip if used in a double rifle, but it would not be necessary in a single shot.

For wht it would cost to build a double rifle I would just get a 450/400 3", but a sincle shot like a Ruger No1 would only need a new barrel.

However I must say that I have killed a LOT of game with a 9,3x74R and find it a very good cartridge.

Interesting idea.

I have a 31 in 7mag that I was going to rebore to a 74R before I realised taht because of the taper it was not going to work.

Interesting indea here I will look into this.

I found this very interesting too:

http://www.thefirearmblog.com/...rauss-a-303-wildcat/

74R case is 2.9" long. 405 is a fair amount shorter.

There's an italian wildcat still in the experimental stage that is a 416" version of a fireformed 9.3 x 74R case, just to pump out to reduce the taper and make a 416 cartridge for breech loading guns, suitable for large game. It is called 416 x 72 R SDG

Perhaps cheaper and more useful route to make a longer .410" version to use 405 win ammo as well as longer 74 brass on a ruger #1 already chambered for 405 win.

A 416 like you describe would be a tough one for us Yanks.

Much of our effort has traditionally been channeled towards the 30-06 family which pretty much limits us to a max diameter of .400 bullets.

IMHO, I would suggest you shrink the overall length just a tad and go down to the 7x65R. Then blow it out to a 400 Whelen chamber with a rim cut-out. In the "other" measurement system, you could call it the 10.5x65R Whelen. I just brainstorming here, so someone local to you would probably have a better idea.

Good Luck!