Howdy,

Is it possible to chamber the 416 Rigby with a Model 70. What would it take to do it? The bolt diameter is measured at around .690" and with one of the lugs sticking up all the way to the bolt face, there should be enough meat for a .590 diameter case head. It looks to me like the bottle neck would be the magazine box. I suppose I can always use lighter bullet to reduce the COL to under 3.6". Any info will be greatly appreciated. Thanks.

[ 10-19-2002, 18:04: Message edited by: Mingo ]

Mingo,
It can be done, but there isn't much meat left on that bolt face when you get done. The best man I know to get them to feed is Mike Kizzler in Boron California. He runs an ad in Rifle mag every month. I don't have his number off hand, but he's the guy to talk to.
Winchester's custom shop was going to be offering that cartridge from the factory, but after looking at the safety issues, they decided to drop the idea. We had to make custom bottom metal for them that opened the rear of the mag box back .144" and straightened up the taper in the magazine to .050" more per side. Somewhere they've got 50 pieces of bottom metal that's not getting used for anything. Guess they'll chalk that up to corporate losses.
There may be some that will disagree with me, but that cartridge is not suitable for that action. When you're only talking about .050" per-side wall thickness, that's cutting things too damn thin. That's why when we manufacture our receiver, we're putting the diameter of the bolt out to .750"-.800". You can't be too careful.

Thanks Matt for the insight. The bolt face opening is the least of my worry as my CZ 550 in 416 Rigby does not have much wall left on the bolt face either and it's been working fine for me. It does not need much material to keep the cartridge in place at the bolt face. Keep in mind that the CZ 550 does not have one of the lugs protruding all the way to the bolt face while the Winchester M-70 does. I was just thinking about a possible project and may not want to get started if it's gonna be a lot of trouble. Again I am willing to compromise by loading the cartridge within 3.6” so I thought it would not take much to get it feed properly in a standard magazine box. Of course, it would need a 416 Rigby follower.

I wonder what would your action look like. I am designing my own action right now with my state of art CAD/CAM/CAE design workstation at work. Everything is being done in 3D solid modeling including finite element analysis. I basically combined some features of the CZ 550 and Model 70 and enlarged it slightly to take all the British and German sporting cartridges of yesteryear. This project is more for fun than anything else as I am not sure if I am gonna be able to start my own company anytime soon. If I ever decide to manufacture it, I would do an investment cast and then finish it with wire EDM. I will try to post some pictures when I get done with it. Thanks.

Ming,

The current Model 70s in 375 already have the bolt stop set for 416 Rigby requirements or perhaps even greater. When the bolt is fully pulled back, the bolt face is back behind the magazine and about half of the middle screw hole is uncovered. However the box is for 3.6" length. So the length would be easy enough. And remember that the post 63 receiver is a about .25 longer than the Pre 64.

Sometime ago I spoke to one of the gunsmiths in Australia about it and he felt it would all be OK but with a possible question mark on the smaller barrel thread if full pressure loads were to be used as normal practice. The problem being that any circumstances that caused an increase in pressure would be increasing the pressure from a much higher base line than would be the case for 400grains/2400 base loads.

Mike

[ 10-19-2002, 08:47: Message edited by: Mike375 ]

Mingo, the M70 can be converted to shoot the 416 Rigby. The conversion is very similar to that performed on a M98 Mauser. You will need to mill the rear bridge to open up the ejector port. Additionally, there must be a clearance cut made to the front action bridge to open the ejector port as well. This is simply a shallow half round cut directly into the front bridge tangent to the action rail about .150" deep. This will allow you to eject spent brass. You need to widen the action rails front and rear. If this is undesireable, and I believe that it is to the extent that it must be done as triggergard pointed out, you can utilize a single stacked magazine. When you are done the rifle will work, but you have cut a GREAT deal of safety margin and stiffness out of the action.

In reality this conversion is approximately equal to fitting a 505 Gibbs into a Mauser magnum action. I think you would be much better off in the long run to purchase a Mauser magnum length action like the CZ550 Safari, Dakota M76 Africa, or the Ruger M77 Magnum. These actions were specifically designed for the big Rigby case.

Axel

Thanks Mike for the info. I know that it can be done but would like to hear some first hand experience so I will know exactly what to do. As for the pressure, it should not be a problem as the 416 Rigby operates at around 40ksi which is way less than the Model 70's margin of safety in terms of pressure alone. Anyway, it was just a thought.

Axel,
Thank you for the info.

Mingo, the current C.I.P. pressure standard for the 416 Rigby is 47,200 psi avg pressure. You are welcome, BTW.

Axel