Home Forums Hunting & Shooting Express Rifles and Big Bores Only 10.75x68- The great littlel big bore

After receiving several emails on this neat little big bore requesting I do a post on it and furnish some loading data I decided the requests had merit as it is a little known caliber..It is very hard to find much printed data on this fine caliber.

My association with the 10.75x68 began some years ago with the purchase of a cute little Mauser 98 in that caliber, I found some brass, and bullets were available as it was a .423 bore ala the .404 Jefferys..It had some interesting balistics in that it duplicated the orginal specs of the .404 Jeffery with a 400 gr. bullet at 2100 plus FPS, and I reallized it had the potential to push a 350 gr. Monolithic (GS Customs in my case) to perhaps 2350 FPS and thats buffalo medicine in anybodys books..To top it all off the neat little round could be made in a 8 or 9 pound o rifle and not be a slobber knocker in recoil..

What more could a buffalo hunter, tracking bulls 10 or more miles a day in the African heat want? This little gun had all the bells and whistles one could ask for...

I took it to Africa and shot a number of Cape Buffalo with it and it worked as planned and with the drop box I opted for it held enough ammo to start WW3 !

400 gr. Woodleigh, Horneber cases,Fed 210 primers
74 grs. of WW748
61 grs. Varget All these loads chronographed 2100 plus FPS
57 grs. Norma 203B

350 Barnes X and GS Customs bullets, and 340 gr. Northforks, Horneber cases, Fed 210
61 grs. H335
56 grs. 4198 2300 to 2350 FPS
58 grs. Norma 203B

380 gr. Norhtforks
66 grs, VV-140 2170 FPS
61.5 grs. VArget 2120 FPS

Of interest is that printed matter is hard to come by and when you find it then it is European powders, but these powders are tranposable burning rates as follows:

2208=VArget, IMR-4064, IMR-4320

2207=H4198, IMR-4198, RL-7

2206= H335,BLc-2



RWS and Kynoch factory ammo clocked right at 2150 FPS

Case Oal is 2.677, Trim length is 2.666

Note: The case is quite long and if you ever intend to change it then about the only round that will clean the chamber is the 404 Jefferys and just barely so I recommend a very competent gunsmith to do such work..

Note: I think those old German smiths just stuck a reamer in those guns and when they had gone in for enough they just called it good and as a result some of the Metric chambers vary a good deal and in many cases one needs to fireform the brass from the get go, then begin his load work up..Therefore my loads are only a guide to go by..

Definatly began 10 percent below my suggested loads and work up from there..Some of the older Mausers, depending on the make and model and maker, could be a tad soft I suppose...

Thanks a million Ray!


Mike

Your welcome.

I find myself with a barrel that is to light in weight in a .416 dia. It's a number 4 contour in SS from Lilja. I can not think of a ctg to chamber such a light weight barrel for caliber, to. I do have a hundred .404 Jeffery's on hand (brass) And think they would be to much, necked down to .416. Any ideas?

I'm not really limited by actions available to me, as I have at least a dozen choices here in the shop.

IMHO, about the only feasible choice is the .416 Taylor, or Ken Waters' .416 Express. (.350 Mag necked to .416)

Ray,

Thanks for the excellent thoughts on the 10.75x68. I have two boxes of new unprimed RWS brass and numerous Mauser actions lying around... I have been thinking about putting one together. Why? I have't a clue. Just something different to play with...

Grasshopper

One of my uncles had a 10.75x68mm built on an Enfield
action, he never shot anything larger than a black bear
his entire life, and never made an overseas hunting trip.
He passed away several years ago, and the rifle has since
"disappeared" as things often do when a person passes away.

sounds very interesting....those ballistics with the 400 grain Woodleighs basically duplicate what I get in my old .450/.400 Watson double. Would be very cool in say, a nice 8 1/2 pound Mauser sporter.

Since you have those bullets, a 400 Whelen would do the same

Much handier than a CZ550 416.

How about that new 416 Ruger?

I second the 416 Ruger as the number one choice, its a given almost...

Using Atkinson math and therory, necking down a 404 case to .416 would be no problem at all, that would be only seven thousands and divided by 4 sides, that ain't much.

I built a 416/400-3" (a 450-400 necked down to .416) double rifle once, still have the dies, not much market for those dies as they have not sold in about 50 plus years! back then it was superlative idea as .416 bullets were available and .423s were rather hard to come by..The guy that bought the rifle wouldn't buy the dies if you can believe that, maybe he wanted a wall hanger!

But the 416 Ruger would be, by far, the best route with brass and ammo readily available, conversion much simplier, and balistics would be the same I suspect, at least close enough that a buffalo couldn't tell the difference and you have the advantage of a proper headstamp (if thats an advantage) plus the availability of factory fodder...

I've got 20 pieces of Horneber brass and thinking of ordering another 40. That'll probably keep me for quite some time.

May try out the TSX and probably order a mold to cast some for it.

Any opinions on the Lothar Walther .423" barrels?

Mike

pintoguy, atkinson.

I'm glad you guys are out there. I would have never came up with the .416 Ruger. That is a name that seldom passes these lips, for some unknown reason.

Buying that reamer wouldn't be a bad idea, as it might possibly get more than one chamber cut?

I was thinking about the .416 Howell, but your ideas won me over. I still have Woodleigh bullets on hand for the .416 from the Lazzaroni Meteor that I didn't get along with.

I think a little research on the .416 Ruger will be in order, I might be lucky and find somebody at a gun show that thinks it will be perfect for moose and bear.

Great idea Gentlemen, thank you.

416 WSM too.

Could you duplicate 450/400 3" from a WSM case? And would it feed? That would be nice, and easily handled in an eight pound rifle.

I love wildcats as much as the next guy, maybe even a lot more. To be a guy that has to face reality in the world, you just have a heck of a time pedaling a rifle that a guy can't walk into a gun store and buy ammo off the shelf for. I wish it wasn't that way, but in fact it is that way.

You can try to sell a rifle with a wildcat chamber with dies and a hundred or more formed cases, and you will be lucky to get more than just blank stares?

I would do a 400 Whelen to dupe the 450/400 NE. It does it, and easily with plentiful cases. The headspace issue is not an issue IMO. A light(er) rifle could easily be done.

400gr. bullets (Woodleigh, A-Square, Barnes) we have used will hit 2,250 with RL-15(66-68 grains in Neal's rifle). We have never had any issues and ES is non-existant. I don't think enough RL-15 or VARGET could be crammed in the case to cause issues; bullet pushing enters the fray when doses get greater.


Yes, the WSM should do it easily in 400 or 416 flavor. Feeding must be built around the case. I don't think the WSM case has as much issue with feeding as bore size goes up, but I honestly have not played with them enough and never plan to!

(Just slingin ideas for those out there who may like them).

Hmm, maybe an RCM case would do it...

About the 400 Whelen, do you need to fireform the cases? No headspace problems at all?

Reloaders Bench

There is a lot more information regarding this issue also from Z-hat. That is why I've stayed away from it.

An RCM case should as well. Anything with '06 capacity should do it, albeit not with large case/low pressures of the 450/400, hence our use of slow (for bore/case size) powders in the Whelen.

Yes, the Whelen needs necked up to 416, re-sized and fireformed. The beauty is that 41 cal. pistol bullets do this economically.

Close to 400 rounds already, no headspace problems. We even tried making it fail by firing with straight cylindrical cases. Not even a hitch. It is a highly unsung round.

3sixbits, Have you any sources that have had headspace issues? I have heard this too but have never even had any trouble whatsoever, nor have I heard of documentated cases.

Ken Howell here has stated that it was never an issue and he himself developed a rifle cartridge that headspaced off of the mouth.

Most 400 Whelen dies are designed in such fashion that the shoulder cannot be pushed back.