I've got an option on a Mauser in 10,75 X 68. Can this be converted to 404 Jeffery easily, as in just a getting it reamed for a new chamber? What would need to be done?

Please, don't. The original caliber works very well in normal sized m98 action, is very useable and have, with modern gun powders, enough power for DG hunt. Shells could be little difficult to find but for example german Horneber makes them.

http://www.huelsen-horneber.de/index_en.html

please dont --

mag will have to be lengthened and then feeding reworked..

you might rethroat it to take 400gr bullets on the groove, though

I second the "please don't", but it can be done. One of our fellow AR members from NZ has a Type A Mauser that was converted from 10.75x68 to 404 with great results.
Matt

Not sure whether I am the AR member ColoradoMatt was referring to but I do have a Type A Mauser that started life as a 10.75x68 and came to me from Africa having been opened up for the 404 Jeffery cartridge.

As pointed out by jeffeosso there is quite a bit of good gunsmithing work needed to be carried out to a standard length M98 action and magazine to make it work properly with the longer 404 cartridge. Rechambering would be the easy bit.

My rifle has been rechambered with a good bit of free-bore probably to handle the monometals around in the late 70's when the conversion was done, but the magazine length, open up to the maximum will only take 404 cartridges with bullets seated to the original overall cartridge length using Kynoch profiled projectiles. That means that the style of bullet such as the Barnes TSX or similar Woodleigh mono bullets will be seated deep into the case. They will chamber and shoot okay but it is the magazine/actionlength that is the inhibiting factor with these bullets.

So too would be the issue if using any of the 400gr bullets intended for the Jeffery in the 10.75x68. Plenty of data around for using the heavier bullet with modern powders in the smaller Mauser cartridge producing the old 404 performance level of about 2100fps.

Personally I do not think that is the full story though when talking of using the 10.75x68 with 'modern' 350gr bullets. The 450/400 3", the 404 Jeffery, the 425 Westley Richards and the 416 Rigby all became exceptional dangerous game cartridges because of their phenomenal straight line penetration much the same as some of the small bores that also performed extremely well on dangerous game in the hands of capable shots, the 6.5x54, 7mm Mauser, 318 WR, all using long heavy for calibre bullets that gave good straight line penetration.

Despite what some will proffer, there is no comparison between the short stubby 350gr bullet made for the 10.75x68 cartridge and the 400gr or now even 450gr bullet made for the 404 Jeffery. In almost all cartridges where velocities are limited to no more than 2400fps the long heavy bullets give infinitely better performance on big game than the light short bullets.

So, like everyone else so far, I would also leave it be and not expect it to perform like a 404 or any of the other great 40cal cartridges if using the 350gr bullets, but if you want a hard hitting deep penetrating dangerous game rifle, I would be going the 404 Jeffery way.

quote:

Originally posted by eagle27:
Not sure whether I am the AR member ColoradoMatt was referring to but...

You are the fella!
Matt

I have a set of dies and a box or two of Woodleigh bullets in my shop...

Yes, its possible but there is 0 room for a mistake, a 404 will just barely and I mean barely clean up 10.75x68..

The 10.75 x 68 is a lot of trouble to find brass and load info, but its a fine caliber and worth keeping original, depending on the gun of course..A 400 gr. bullet at 2100 FPS and a 350 gr. Barnes or Woodleigh at 2375 FPS is an awesome killer of big mean stuff...

I'd love to see pictures of the gun, maybe we could work out a trade for something more suitable to you.