What is the nature of the modifications required for this? I already have dimensions (length and width) for a proper sized 416 Rigby mag box.

Thanks,
Todd

Todd,
Email PME and talk about it. He was nice enough to send me a great article on that, including dimensions.. but it's not "at hand" right this second..
jeffe

[ 01-20-2003, 01:13: Message edited by: jeffeosso ]

Todd, if you could, post those dimensions (along with your magazine box measurements), I'm quite curious as I'm sure others are too. Thanks - Dan

Dan,

Jim Wisner of PME was kind enough to provide me these specs when I was looking in to building a 500 Jeffery on a P-14.

Rigby max box dimensions:
1.050" Rear width
.850" Front width
3.850" Length

The only thing I'm not sure of is depth, but that could easily be figured out by rubberbanding three together in a stagger and measuring the height (thanks RGB for that tip). Any takers on that experiment, those of you with 416 Rigby ammo lying around?

I'm hoping that a simple taper, like on the straight rail Mausers Jack mentioned a few posts down, would work. This would be easy and cheap to machine. If it ends up costing $$$$ to modify the action, damn the nostalgia, it would be easier to just buy a CZ.

Todd

Some time ago ACGG Gunmaker paper had an artile on these mods. Could have been by Wisner.Mark

Perhaps one of our ACGG members could give some pointers on getting a copy of this article?

On a side note, has anyone else noticed how brilliant the Enfield designers were? Granted they stood high upon the shoulders of Mr. Mauser, but look at the feed ramp, for example. Where is it? On the mag box, a simple cheap part to replace when military cartridge design changes, requiring alteration of the ramp for proper feeding. Still not as sexy as a 98, but admirable in it's own right.

Todd

Todd

Check your e-mail

Daniel

Todd, and anyone else on this line of wonder.
Any three supposedly identical cartridges when bunched together, two laying next to each other the third laying nested between the two forming a clump would if you want to dig out a protracter form an equilateral triangle in the lines you draw at dead center each ctg. We are talking 60 degrees per angle. That is the Mauser Brilliancy.
To determine magazine widths:

Diameter of ctg at a point about .200" forward of base. For Rigby call this .591"
Sine of 60 degrees is .866025 for your hand held number cruncher. Add 1 for 1 each diameter to the sine. This becomes then 1.866025 Multiply .591 by 1.866025. Result= 1.1028

Shoulder. Max ctg per B.R.P & Treble .540"

.540 multipied by 1.866025 Result = 1.0076"

If you narrow the box by .053" at the rear you take same ammount off width at the shoulder. Whatever it comes out at 3.775 length or 3.825 is simply a continuation of this taper.

For best results when you are able to do so the width of the receiver lips should be about .010 over case dia. at the rear end . This keeps that big fat case down to where it will not interfere so much with EJECTION.

The feed well walls of the receiver should match the magazine inside walls, taper for taper. In addition the receiver feed walls should have Mauser's vertical taper of 8 deg. per side narrower at the top.

Stack highth. Take an adjsustable parallel, set it to width of magazine box at rear .200 mark, place on vise parallels or a piece of something flat ,place the 4 ctgs base down on the adj. parallel, run a square from vise jaw to vise jaw touching one ctg. Same drill 4th ctg opp . Stack highth is distance between the square's blades.
Allow about .140 for spring eye and follower platform flat and another .060 to that so you can depress the top ctg,full magazine to dump a 5th round into the chamber, without getting a twofer.
End of bullet ramp should come out even with the Military alignment slot for their feed nose, Rest of magazine length to rear. You will need a newly made bolt stop. Dont do it half assed and weld a new stop lug on the old one! Last thing you do is to cut away the feed lips and widen out the bullet ramp. If you do not use the Mauser Bump over system in the receiver, (I don'T) you will at the end have a feed lip geometry that reminds you of the top gunwales view of a small row boat. The front lips become the guide in a straight, line narrowing to the bullet ramp cut and this guides side of ctg direct to center of chamber. Amidships the width accross the lips will be around .725 for a distance of about 3/4" starting about 2 " from case base. Stay the course.You seem to be a gutsy guy who can and will make it work.
Sine formula works for Mauser style magazines, whatever ctg. Largest dia at rear times sign and if you roll the ctg on a desk top and find that the bullet touches the top not shoulder, not even neck- then that is where you get that diameter and that is the starting point for width at that point. I wrote this up once to be included in a guild newsletter, probably 8 year ago. If you follow the procedure you will not be messing with the W spring trying to get way more tension at the back or the front simply because the ctgs.pinch at that point.

System98 thank you for the very nice description of how to calculate the mag box dimensions. Very clear!
Brent- I have Jim's article and he goes into exactly how to open up the action both in the front and rear to feed a 416 Rigby. I used his procedure to open my 1917 Enfield up for a 470 MBOGO ( .416 Rigby with the shoulder moved foreward and .475 caliber) and it worked very well. You will need a vertical mill and some good carbide 3/8 ball mills for the job. As System98 said the bottom of the rails need to be at 8 degrees and the way Jim does this is to tilt the head of the mill 8 degrees. The biggest issues is making a Jig to hold the action inverted so that you can mill it without squeezing the rails. I made mine out of 1 inch steel plate with clamping bars to hold the bottom of the action down. Making this fixture took way longer than converting the action! I also used this fixture to hold the action to modify the feed ramp by angle milling.-Rob

Thanks to all for your input, especially Mr. Burgess. I'll have some fun playing around with that info, after I get some Rigby cases. I'm surprised by what I have heard from other people (this topic generated a few e-mails to me), re: the number of Rigby rounds they can get in a properly widened, standard depth mag box (4!). I would have been happy with three.

Any more suggestions / hints / comments are certainly welcome, as are pointers on where to find that article. I'll probably start with PME.

Todd

Altering Enfield Actions to .416 Rigby and .505 Gibbs by James Wisner as told by Steve Nelson appears in two parts of the Gunmaker Issue #79 and #80 of 1997.

Mr Burgess has covered this already very well but also in issue #79 Wisner has an article on magazine boxes.

All three articles are very informative and have some very good diagrams.

Thanks for the info, and where would one find issures of The Gunmaker? - Dan

As Dan , I want to know where to find this magazines , System 98 thank you for the description and the tips on the conversion , also antoher point , what's the best follower , I use a CZ 416 , but it's narrow than the magazine box , and the measure for this is at rear 27.5 mm ( 1.08") and at front 24.5 mm (0.96")long 95 mm ( 3.7") deep 42 mm (1.65" same as the original ) and hold five 416 rounds .
Saludos Cordiales

Daniel

Dan and Daniel

You can get all the information you requested plus a lot more at www.acgg.org