I have a custom built .375 H&H on a Whitworth Mauser. The rifle has a beautiful custom stock but no drop magazine. I saw Safarikid had a 585 Nyati posted for sale on 2-24-17, by an unknown builder, that has the exact type drop box I am looking for so I wouldn't have to modify my rifle. Does anyone know who builds this type magazine and could I have one built for the Whitworth.

Thanks lindy2. I looked at their site before making the post and couldn't find any photographs of what their magazine might look like in a standard stock. I really like the design of the magazine on Safarikid's 585. With the lever release on the bottom and the extended magazine it looks a lot like the old Westley Richards design they used on their .425.

Whoever made that was pretty talented. It appears to be a regular Mauser unit that had the triggerguard cut off and welded back on at the top of the magazine. Then some extensions welded on at the top of the magazine, and then the floorplate reworked to be a hinged floorplate, and then a lever release attached to the floorplate.

Lots of careful work!

For an idea of how smiths rework a mauser unit for just the hinged floorplate with the lever release take a look at pages 231-242 of Jim Carmichel's book entitled "Do It Yourself Gunsmithing".

Yes they really knew what they were doing. I looked at Westley Richards web site today, under their Build Your Rifle section and they still show the extended magazine as an option. The price for that option alone is 1750.00 pounds.

I think I understand what your discussing - which is an extended floorplate for a standard depth stock. Here's a couple of options for you:
http://www.customgunandrifle.com/products/floorplates

I believe you talking two different options, the drop box or the extended magazine..To me a drop box has to be stocked for the wood to surround the deep box ala most big bore custom riflesf, English rifles. They normally hold 4 and in some cases 5 down.

The extended magazine has bare metal coming down and can hold any number of rounds. I built a 404, a 375 and a 416 over the years with extended magazines to hold 6 down on REm mod. 30 actions (Enfield)...Dennis Olson did the work for me on one or two of them and the late Tony Barnes did one..They worked out real well and that's what I would do with your Whitworth, you can have a quick release box or a solid box.
I liked the solid box as its foolproof. The QR box adds a little length and they have been know to pop open I suppose, usually gunsmith error btw..I don't mind running the rounds thru the gun to unload one, and by doing that I know they will feed, not a terrible idea with dangerous game.

Just my two bis based on 3 or 4 guns Ive done this way.

The extended magazine you described is what I'm looking for. My rifle has a nice custom stock made for the standard Whitworth bottom metal and I don't want to change the stock. I'd like to see an example of the extended magazine if anyone has a photograph they can post. The only one I've looked at is a photograph of is the old Westley Richards style.

Steven,
I can send you some pictures of a a custom 404 I did on an Enfield..The extended box was done by Dennis Olson. Won't change a thing in your stock..Will need you to email me at rayatkinsonhunting@gmail.com to send a picture to your email...I can't post on AR..Im pretty much computer ig..

Ray,
Thanks, I will send you my email. I can't post on the site either and probably have as much trouble operating a computer as you. You can't hardly get by without one but they drive me crazy.