This post is following on from the takedown thread.

I would appreciate any info or help for this project. Originally I was thinking about a practical .338 Win Mag but Safari-Hunt went and re-kindled my fire for a 8x68S with his post.

Questions:

Q1. Who makes a Mauser 98 actioned rifle in a classic style that is chambered for the 8x68S cartridge? CZ?

This rifle will form the foundation of a project to build a takedown rifle with a barrel in 8x68S (24 to 26" barrel), 6.5x68S (26" barrel) plus a "heavier" calibre which might be a 9.3x68 wildcat or a .416 wildcat (10.57mmx68).

The rifle would need to be fairly light as I want the 6.5mm to be able to be used as a "mountain rifle" in NZ. The 8x68S can be reasonably light as well. The larger calibre may be able to be made heavier with a heavier fore-end and possibly using removable "recoil tubes" in the butt (similar to the tungsten balls in the Blaser 93's).

I like the idea of a 416 for the heavier calibre due to the choice of bullets, though if this was unrealistic a 9.3mm would be great as well. The 416 combination would also allow 400 gr projectiles to be used for DG, plus may allow more of a shoulder than say a .423 (10.75mm)

I would be using 3 different scopes in quality QD mounts so re-sighting would not be a problem. The rifle would be a takedown with two plates inserted in the fore-end allowing the action and receiver to be separated from the barrel and fore-end. A "switch" would be used on the bottom of the foreend allowing rotation of the barrel to be fixed in place. 3 separate foreends and one action etc.

Q2. Does anyone know what sort of velocities a 10.57x68mm would produce with 400 gr bullets? (Note I am not talking about the existing case the 10.75x68 which is a different case).

Water capacity of the 8x68S is 84.8 grs. The 10.75x68 with a thinner case has a capacity of 94.8 grs and produces 2200 fps for 350 gr projectiles.

I guess I would be looking for at least 416 Taylor performance of 2100 to 2200 fps with a 400 gr projectile. Which is also similar to the 450/400 3" NE.

Takedowns can be made with the barrel thread having grooves can in them (usually 3 or 4) allowing the barrel to be inserted and locked in place with a quick twist OR the threads untouched meaning the barrel needs to be screwed in as normal before being locked into place.

Q3. Which method is preferable - is wear on the threads significant? Someone mentioned there are means to adjust for wear, any idea how this is done?

Q4. Any other ideas - is this sensible (probably not from a cost point of view) especially in terms of feeding?

Thanks for any help or information. My first step is just to get an 8mm and then proceed from there.

John, I am working on 9.3mm and .416 cartridges based on the 8x68s. There is another gentleman (Bear Claw) on this forum that is working along the same lines, but I haven't been able to contact him via E-mail or PM. Ken Howell thinks there is plenty of shoulder to headspace the 416 provided the proper angle, who am I to disagree. My question to you is, what action(s) are you considering? With the case length of the 8x68s bullets can be loaded to 3.5"-3.6". I would think that a .416 on this case loaded out that far would be able to exceed the 416 Taylor. Wish I could help on the take down part, but I have no experience there.

DOC

NOthing new here, we have had the 10.75x68 for 200 years that is the 404 x 68....no difference in that and the 416. It never came close to equaling the good old 404 J., 425 WR. or the 416 Rigby

I think your cheating yourself by not using the 404 Jefferys case....The Krouts figured that out 100 years ago. Dakota, Remington, and a bunch of others are now taking credit for the same thing the Germans did way back when...Most are merely re-inventing the wheel...

As an after thought and a user of the 10.75 x 68, it is just barely equal to the 450-400 and does it at very high pressure...Brass for 68 is a major problem, so much so that I had my 10.75 x 68 converted to a 404 Jefferys by rechambering and adding a 404 Blackburn bottom metal....Bertram brass was lasting max at 2 firings with rather moderate loads.

Mr. Atkinson,

I was under the impression that the 8x68s cases were a good bit larger in diameter than the 10.75x68 and that the 10.75x68 was only loaded out to 3.15" or so in order to work from mauser magazines. Maximum case measurements for my proposed .416x68 are: .512" rim, .524" base, .498 shoulder, 2.182 length to shoulder, 2.27 length to shoulder-neck juction and 2.655 trim to length. These numbers are based on a 26.5 degree shoulder. Loaded to 3.55" this case should have 10-15% more usable powder space than the 416 Taylor and 3.37"(not that you can't load the taylor out). RWS makes excellent brass that I can get for about $1 per case delivered from Germany.
I am looking for 2420 fps from a 24" barrel using as little powder as possible. This would appear to me to be the ticket.

DOC

Ray

I know your previous comments about the 10.75x68 and the difficulties that caused you to rechamber it to 404.

404 sounds like a better cartridge to me than what I suggested, but I am looking to have a takedown with the same base size ie the 8x68S, 6.5x68 and a wildcat in 9.3mm or 416 (10.57mm). Plus I think the 404 when necked down to 8mm or 338 plus a 6.5mm will be overly powerful if I went the other way. I would be planning to use a 8mm and 6.5mm for all sorts of game and in the 68 case they have ample power already.

A different solution - not sure if it is sensible or not - would be to use a different bolt and use a 404 barrel with it. Feeding problems? How easy is it to get a second bolt? (By the way my Mark X bolt works in my Parker Hale OK as does my FN Mauser bolt - with out firing anything of course).

The 10.75x68 is a different case. I was told about a year ago that it would work with a 8x68S.

Thanks for the reply anyway. By the way what problems did you have with your "switch" barrelled rifle, or was it a takedown? Thanks

DOC

Thanks for the info. I would like to correspond with you as you seem to be further down the track than I am. Will send an email.

I was thinking of a CZ550 or ZKK602 (same action) or failing that finding a Parker Hale Mauser 98. Not sure yet if I can get a 8x68S as a factory rifle or need to build one up from scratch.

Are you using a standard length action?

[ 11-07-2002, 06:04: Message edited by: NitroX ]

The Rem Ultra Mag cartridges use a 404 case with slightly reduced rim; however, it ought to be close enough for your needs. I think that the same is true of the Win Short Mags. Several of these would be in the range of the 6.5. Just a thought. Ku-dude

9.3x70 anyone? Check back issues of Hatari Times, Harald Wolf built a rifle for this pre WWII cartridge. Quite a performer.

(Hint: Think 404 Jeffery case necked to 9.3, with a little shoulder work, and you have the 9.3x70. There was a thread on AR a year or more ago on this cartridge.)

There is what i've been tinkering with.

The one on top is the 8x68 simply necked up to 9.3 with no other changes. That ring left at the on the neck is from the original juncture at the base of the 8mm neck. The second is the 9.3x64 & third is 9.3x62 for comparison. I used Hirtenberger brass because OWS had it on sale & it was inexpensive. Since the Hirtenberger brass is so thick .060 at the base immediately above the web, & just barely larger in diameter .5055 for the 9.3x64 versus .5205 for the 8x68 case & viruraly the same diameter at the shoulder that the x68 brass could be swaged down, cut to length & the extractor grove recut to 9.3x64 dementions? Shouldn't a 9.3x64 sizer die be able to do this swagging? Your only looking at .010 reduction in diameter at the base & less higher up on the case. If this is feasebly it would certainly be an inexpensive alternative to RWS 9.3x64 brass. By the way the Hirtenberger brass is $7.50/20 from OWS. Yes, no, maybe? What do you think? If anyone has 9.3x64 dies & would like to try to swage some x68 cases I will be glade to send you a few cases to experiment with. If it would work it would breath a little much needed life into a fine cartridge.

PS: Doc sorry for not getting back to you my server has been playing games with my abiltiy to send mail.

[ 11-07-2002, 23:45: Message edited by: Bear Claw ]

Bear Claw,
I would be delighted to try your theory. The idea of cheap brass for my 9.3x64 sounds too good to be true. Cobalt

Cobalt send you address & I'll send you some 8x68 cases to try.

Bear Claw,

How is quality/consistency of the Hirtenberger brass? The RWS brass is fantastic. It also seems to be of heavy construction. You are a step or 2 ahead of me, I am still waiting on an expander to neck up some brass. On the dummy round in the photo, how much does the neck thickness vary before and after the ring? What is the diameter of neck with the bullet seated? The necks om my brass seem to be on the thick side, which is supposed to ne normal for this cartridge, but Hirtenberger is reputed to have problems with thin necks. Have you checked your case capacity? I hate to be a bother, if we can share information maybe we can save some time/money.

Dave

Doc you have mail.

The neck diameters are as follows.

9.3x62 factory Norma round____ .388

9.3x64 factory RWS round______.388

9.3x68 (Hirtenberg necked up)___ .393 (seated with 286 gr bullet pulled from RWS ammo).

338 win. factory round _________.3655

338x68 (8x68 necked up)_______.368 (seated with Hornady 200 gr bullet).

The neck wall thickness on the Hirtenberger 8x68 cases are averaging .0105 thick
with a high of .012 & a low of .009 after measureing 20 virgin cases. It's thicker than
out stuff.

[ 11-08-2002, 21:21: Message edited by: Bear Claw ]

Doc,
You are correct but I was only referring to power wheel...the 8x68 necked up to 10.75 (404, .423) would be about the same power in every respect...

Nitro,
I always had the wrong barrel on the damn thing for the game I was looking at!! They are very difficult to keep sighted in, at least in my case they were (had a couple of them)...All in all I think they were a nuisence...rather have two rifles. But someone else may love them.