Well the 284 was made in the 1st place to try to give 270 Win ballistics from the new short M88 and M100 It was Winchesters attempt to give 30-06 powder capacity to a short shell.
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So if I were wanting 284 ballistics from a Mauser, doing all the action work to make it feed is somewhat of a worthless endeavor when you can simply make a 270 Win or 280Rem out of it, and then not have the nightmare of getting 284 brass. The 284 will no nothing better then the 280 Rem.

As far as making a 9.3X62 goes, that super easy if you have the original GEW length Mauser to start with. It's important to know you overall length of the magazine is OK beforehand because the GEW length used by Otto Bock for the 9.3X62 is a not the same as the dedicated KAR length made exclusively for the 8X57 in the WW2 years.. If you have the shorter mag box making a 9.3 is possible, but not fast and easy. It would be like like making a 375H&H out of a GEW length, you'd need to extend the front of the box and re-cut the feed ramp.


I understand you don't want an 8X57. Just your choice, and we all have out preferences. I love mine and it's a wonderful hunting arm. Deer elk and antelope have all fallen to it and it's been a delight to carry and use.

[Linked Image from live.staticflickr.com]OLYMPUS DIGITAL CAMERA by .com/photos/156296479N08/]Steve Zihn, on [bleep]
[Linked Image from live.staticflickr.com]OLYMPUS DIGITAL CAMERA by .com/photos/156296479N08/]Steve Zihn, on [bleep]
And here is my 9.3X62 I made on a Mauser. (GEW length mag box) I made it to take 5 rounds in the mag and the stock is hand made, like the 8X57 above
[Linked Image from live.staticflickr.com]OLYMPUS DIGITAL CAMERA by .com/photos/156296479N08/]Steve Zihn, on [bleep]
[Linked Image from live.staticflickr.com]PA170008 (2) by .com/photos/156296479N08/]Steve Zihn, on [bleep]