Originally Posted by irfubar
Originally Posted by TRexF16
When I had a 1903 Springfield rebored to 9.3x62 by JES, I grabbed a new Hornady New Dimension FL sizing die off eBay for $15 while I was searching for a full set. It has turned out to be one of the most precise and accurate dies I ever owned. I very carefully measure the effects of all my sizing dies on my brass, testing for runout. These are near perfect. The next one off the line might not have been, who knows.

That said,
The shoulder being further forward on the 9.3 than the '06 is a big deal. You can't just neck it up.
Rex

Here is a 286 Privi seated to touch the lands. As you can see it has plenty of room to seat further out.
Next to the Privi is a 286 Partition, it could also be used for fire forming, kinda wasteful though...
As for the 30- 06 brass base being smaller, it's a one time deal, your 9.3 die will not size it back down, leading to repeated stress.
This pic should remove any doubt as to whether I am making things up


[Linked Image from i.postimg.cc]

Thanks for the follow up and I was of course NEVER implying you were making things up. But I will say you have a most unusual chamber. It's great that you can jam the lands and thus effectively fireform necked-up 30-06 in one step.
But the OAL where the 286 Privi touches the lands in mine is 3.53". For the 286 Partition it's 3.59". This is a JES re-bore with what I understand to be a pretty standard 9.3x62 chamber. The OP wrote he was having a 30-06 "hollowed out" to 9.3x62, which implied to me a rebore, and I would expect it to be JES's. If this is the case I don't expect him to have the advantage of such an unusually short throat, thus my comment:
"I would have expected the long, tapered throats on the standard 9.3x62 chamber to preclude that. Especially with the Privi 285 being such a short bullet.
Have you (or anyone else) successfully fireformed 30-06 to 9.3x62 by jamming the lands?"

Thanks for answering back and confirming that indeed you have.
Interested in what the other 9.3x62 owner's throats allow. Are there any more as short as ibfubar's?
Sir, what brand is your rifle, and is it a factory or custom barrel?
Thanks,
Rex