Your note on magazine box geometry prompted me to measure the mag box Gene Simillion built and installed on my M-70 Classic when he built the 460 G&A. That cartridge is based on the 404 Jeffery case, the example you provided. The mag box is wider and completely enclosed on its sides, front and back; there are no windows.
Interestingly, though it fits flush with the belly of the M-70 factory wood stock, it fits 4 460 G&A cartridges. The stock recess for the box has been slightly enlarged laterally internally, though almost imperceptibly. As a test I also confirmed that the box accommodates 5 belted magnum cartridges. This magazine also uses a custom made follower which has a subtly formed shallow groove which causes the left sided cartridges to straighten into the middle of the feed ramp as they feed. Interesting idea which makes for extremely smooth and reliable feeding.
Seems there are several interesting ways to skin the increased mag capacity cat. I like the flush fit because it preserves the lines of the stock. However, that’s a purely aesthetic personal consideration.
For sure, the magazine box cat can be skinned more ways than I can shake a knife at that cat, to mix metaphors. The Ruger Hawkeye box width at back is only 0.925" which is too narrow according to Mauser Cosine Rule. Think of all the big bores done by various commercial makers. None other than Heym makes a cartridge specific box, even up to .505 Gibbs size, from what has been reported. One of the few perfect boxes I know of was the Pre'-64 M70 .300 H&H and .375 H&H. They held 4 down in .375 H&H while the M70 Classic from Connecticut held only 3 cartridges down in the box. There the Pre- had a wider box and same depth. etc.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
