| eagle27 |
| (.400 member) |
| 26/03/23 08:16 AM |
|
Re: A Mauser 10.75x68 Oberndorf Model B Safari rifle comes home
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One other factor is barrel rifling twist. Are the rifling twists of the 10.75 and .404 the same? This also has bullet choice impact. Perhaps Buckstix knows for his new rifle?
The barrel twist is the "16.5" that is stamped on the barrel. I don't know the twist rate of a 404.
The Mauser, Oberndorf factory used the same 420 mm = 16.5” twist length in their .404, .416 and 10.75x68 barrels. See page 275 of on Speed’s Mauser – OOSR book.
Not sure why there is a difference between Speed's book and the data from a Mauser catalogue circa 1910 reproduced in Ludwig Olson's book 'Mauser Bolt Rifles' which lists the 10.75x68 twist as being 14.17" in a barrel length 23.62". I can confirm by measurement that my Oberndorf Type A standard length Mauser which was a 10.75x68 (now opened up for the 404J cartridge) and was manufactured in the same year bracket as buckstix's Mauser, has same barrel length and twist as per the Mauser catalogue data.
This twist rate stabilises 400gr bullets perfectly giving good accuracy from the 'original' 10.75x68 barrel on my now 404 Mauser. I imagine Mauser would have standardised on one twist rate for it's 10.75 calibre barrels.