I need the mag box dimensions of the Rigby mag box. PLEASE HELP!

First attempt at search function:
Turned up just this inside-box rear width, in bold below: 1.025"
That is the critical measurement.
All the rest easily follows after that.
The inside box length is about 3.8" like all the rest.
Don't have rifle in hand at the moment,
but I have measured it in the past.
It is a shallower and wider box than most .416 Rigby rifles.
Easily holds 3-down in .416 Rigby, no more.
But it comes closer to the Mauser Cosine Law box width,
for .416 Rigby,
than any other factory rifle out there.
**********************************************************************************************

From the "404 Jeffery History":

Some of my personal collection of "make-do" boxes:

Dakota M76 African for .416 Rigby: 0.975" inside box rear width

SIG Arms "Mauser Banner" M98 Magnum Mauser for 450 Dakota: 0.995"
Close enough to 1.000" like a pre-64 M70 in .375 H&H, that I guess it would be best on a .375 H&H,
and would hold 6 down in .375 H&H instead of only 4 down in 450 Dakota.
Is this the same box used for their .416 Rigby and 500 Jeffery too?
Ah, well, it is built like a bank vault (integral thick-walled Mauser box) with drop belly stock and coffin floor plate too, and it works.

Ruger M77 RSM Generation II in .416 Rigby: 1.025"
Close, but no cigar.

The Duane Wiebe Bank Vault Box for the 500 Jeffery is 1.020" inside width at the rear of the box, and holds 3 down.
Massive box front wall thickness, will never get a dent from a bullet nose.
Add the coffin floor plate and it holds 4 down.
If it works for 500 Jeffery, it will work even better for the 49-bore/.500-caliber/.338 Lapua Magnum Improved of 2010.
Sometimes we just have to make do.
************************************************************************************************************************************************

Review of ideals:

Some ideal box widths at the rear according to CIP maximums:

.375 H&H rim diameter of .5318" and belt diameter of .5339" maximum: box width at rear = 1.86603 x 0.5339" = 0.99627"
This is more than enough, since manufactured brass is always smaller than the CIP max.

404 Jeffery head diameter of .5429" maximum: box width at rear = 1.86603 x 0.5429" = 1.01307"

.416 Rigby rim diameter of .5902" maximum: box width at rear = 1.1013309"

500 Jeffery head diameter (rebated rim abomination, rim diameter 0.5751968") head diameter of .6188976" maximun:
box width at rear: 1.86603 x .6188976 = 1.1548814"

.505 Gibbs rim diameter of .6401574" maximum: box width at rear = 1.1945529"

Forget about adding slop unless using the "rubber band method" to measure.

Using the max spec brass diameter will build in enough slop since the manufactured brass diameters are smaller than max spec anyway.

Man I gotta learn how to use that search better, searched for an hour.....thanks RIP

Yep,
To winnow the chafe, you have to get creative with the search, like recalling that box dimensions were discussed in the "404 Jeffery History Thread":

quote:

Originally posted by RIP:
Oh drat, I left an eraser crumb on the scanner:



The cartridges stack into an equilateral triangle in cross section,
so the case head diameter determines how wide the box should be inside, at the back.
And about 0.010" of extra slop inside the box does not hurt, better than too tight ...
like all the other make-do boxes for cartridges bigger than the 404 Jeffery in the case head.

RIP or anyone, do you know if it is the same depth as the standard M77 Mk II mag box (i.e. for the 300 Winmag)?

Looks like it is very close to the same standard by stock belly depth and shallow floorplate.

Floorplate, follower and spring have a lot to do with functional depth of box.
You can easily work on modifying depth of box.
But you can only go so wide or so long and still get the box to fit in the action,
whether it is sheetmetal or thick-walled integral bottom metal.