I made two spacers (about 2 mm thick) and put between the magbox and the stock in my 416 Rigby and now it will hold 4 down quite easily. No other modifications.

Is there something I forgot to think about doing this? Is it a stupid idea for some reason?

Im making a new stock and thinking about making it a litle deeper than the original one.

Advice..?

(Im delivering the rifle and a new 458 barrel to the smith this weekend for my 450 Rigby )

Thanks guys!

Hi Thomas,
When you do your new stock you can have a deeper box made for you. I did this with my new 470 Mbogo and it will hold four down and one in the chamber. I think the box was .2 or .25 deeper than the original. You may have to get longer action screws made. With the CZ550 the trigger comes out with the action. Mine is a 602 so the trigger stays with the bottom metal so you have to make sure there is still enough engagement with the trigger. When you go to the 450 Rigby you will end up with an improved case so you might want to modify your follower so the bottom cartridge will lay flat against the follower. This will also ensure max cartridge capacity.
Take care,
470 Mbogo

Thanks for the advices, I will deffinitly try to get a deeper box.

Will the modified follower do for the 416 cartridge and 338 Lapua cartridge or will there be some problem?

I must say that Im not going to africa for any foreseeing time, its just for the fun of it that im building this switch barrel. If I ever can afford the trip I will take the original 416 barrel. (Perhaps I shouldn't mess with the follower at all...?)

Hi Thomas,
I can't remeber if the 338 Lapua is a blown out 416 case or if it has the original 416 Rigby taper. If it is blown out the same as the 450 Rigby then the modified follower will work for both cartidges. If you make the box deeper try and see how many fit in the magazine. If it is just a little shy then try the follower. My rifle which is a 602 will hold 4 470 Mbogo's in the mag and allow the bolt to close on a chambered round. I don't have it here at the moment or I would measure the depth of the box. I just took the old one to a sheet metal shop that had a plasma cutter and asked him to make the box .25 deeper. I had three made and he charged me $10.00 each.
Take care,
470 Mbogo

Several things come to mind, you may change the angle of the box very easily and feeding can be a problem; you may weaken the stock ability to handle the heavy recoil; you weaken the magazine sping as it is at its full lenth as is...

Probably better is to make a new thicker floor plate that is cut out inside to extend a few thousands deeper, thus lowering the magazine without disturbing the fit and function on the feeding end, I would use a stronger spring also.....Modifying can be risky business if your going to hunt DG, so through testing is absolutly necessary, at least 200 rounds fired fairly fast without heating up the barrel is required IMO....

The CZ 550 will hold 6 458 Lotts down, 1 up, now thats some kind of DGR....Just food for thought.

Regarding the case tapers of the .416 Rigby and the .338 Lapua: They are the same. The same follower should work for both.

The .338 Lapua does have a shorter base to shoulder length (0.168" shorter) and shorter overall length (0.179" shorter) than the Rigby, and a 20 degree shoulder angle per side, instead of the 45 degree Rigby shoulder angle. But the step down from shoulder to neck is, of course, a much bigger step in the Lapua.

The 450 Rigby is indeed blown out a bit at the shoulder (about 0.031" diameter bigger), and the base to shoulder distance is about 0.011" shorter in the 450 Rigby than the .416 Rigby. The shoulder angle is the same, 45 degrees per side. The 450 Rigby is not simply a necked up .416 Rigby.

The .375 Lapua is simply a necked up .338 Lapua Magnum.