It predates the .41 Remington a couple years. Norma loaded the ammo. Making the cases from .30-.30 is a bit laborious (rims too big and thick) so I use special lathe turned .41 REM and .40 S&W dies. Trimmed to 1.27” as the old gun requires. It’s basically a rimmed version of the much later 10mm Auto Magnum.
From my experience all the rounds you mentioned are no more robust than the common .30-30. I’ve made .375 and .225 Win. from .30-30.
The Herters round was ahead of its time, a real in-the-middle .400 round. Better filled the .357 and .44 (actually .43) gap. A boy named Lee Martin did one too, a little longer, but arrived at the same place. Gary’s .401 GNR gets there lots easier, .44 Mag necked to 10mm. A little brother to the .410 GNR!
![[image]](images/uploaded/202605120354056a02a45d13a61.jpg)
![[image]](images/uploaded/202605120347206a02a2c86b6db.jpg)
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400 GNR - Short?
- Keith, 2026-05-11, 18:42
![[*]](themes/default/images/complete_thread.png "Open whole thread")
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Yes, it’s called the .401 Herters Supermag
- WB, 2026-05-11, 20:55
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No, not quite
- Keith, 2026-05-12, 18:37
- I think the .400" is too big for a .30-30, .225, whatever - WB, 2026-05-13, 13:10
- 401 GNR #2- 445 SM necked down (nm) - Sean Harper, 2026-05-12, 04:34
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No, not quite
- Keith, 2026-05-12, 18:37
- neck ream - AlanT, 2026-05-11, 19:19
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Yes, it’s called the .401 Herters Supermag
- WB, 2026-05-11, 20:55