Recently bought a rifle in 10.75x57. Sporter stock and 25" barrel. Front receiver ring with BUN marks and stamped GECO. The left side wall stamped SIMPSON L T D G 'BURG IL over M-98 10.4mm GERMANY. Barrel markings as: E K BUG then 10,4mm then 57 then 6/31.

It has an Orberndorf style bolt handle but a round bolt knob flattened and grooved. Barrel looks to be in very good condition with sturdy soldered sight package and sling swivel. The stock is reinforced with a through bolt.

From my research, the 10..75x57 was a precursor of the 400 Whelan round but with bigger diameter bullets. If the Whelan round had a small shoulder then this round has less!

Can anyone tell me more about this rifle and the round it shoots?

Thanks in advance

Believe that was a factory Mannlicher round. They also did a 9.5x57 that was popular. That's about all I know. Don't know if the rifle has any value or what condition it's in. if it's not much value, then maybe it could be rechambered, opened up, and the bolt face enlarged to make it a 10.75x68 Mauser.

BTW - Z1r - Mike McCabe - appears to have a lot of info on this cartridge. I'm sure he will chime him. I read his post and his bore slugged to .426 so he nixed the x68 option.

Here's mine. Rather pedestrian but I like it. I contemplated the 10,75x68 too but brass can be difficult to find at times.

There are likely to feeding issues that would need resolving as well.

I have enough .416's that I decided to leave it as is. Besides, 8x57 and even 9,3x57 brass is inexpensive and easy to find.



Here's a 9,3x57 case in the muzzle:



Mine was also made by GECO and also imported by Simpsons.

It was loaded with 347 gr bullets at around 2100 fps but I have been having fun shooting 265 cast bullets sized .426". Basically duplicating .444 Marlin ballistics. The cartridge can almost be thought of as a rimless .444 Marlin with the addition of a tiny shoulder. However, pressures can be substantially higher than the Marlin round thus increasing its effectiveness.

Got pics?

Mike, my rifle is a copy of yours. Thanks. Has anyone found loading dies for the 10.75x57 mm? I have 200-300 rounds of Horneber brass in 10.75x68. I tried some commercially loaded rounds in this action and they seemed to feed from both rails. Although they would only partially chamber as one would expect! I have all I need to go on with this project. Bullets, brass, dies. Should be easier to adjust feeding than get dies and correct brass??? This action, was it made by GECO? Is it as we'll made as an Orberndorf? ( I hate auto correct on specialty sites)!

How do you load for this round. Called 4 commercial reloaders to buy ammo, no luck. Apparently no one has dies available. I can anneal and use my collet die sets to expand the cases enough to make the brass but I really need dies to make it work. I think. Since this is a rare caliber but not an extremely rare rifle, I may rechamber to 10.75x68?!?!

Here are three links to another forum.

http://forums.nitroexpress.com...arch=true#Post236693
http://forums.nitroexpress.com...arch=true#Post173366
http://forums.nitroexpress.com...earch=true#Post58203

RCBD makes custom dies priced at around $285 for either cartridge. CH4D does too at about $185.

As far as manufacture goes, GECO (Gustav Genshow) didn't make the actions; they were either military or commercial Mauser 98 actions. I am not sure they actually built the rifles either as they were a big dealer and distributor and I understand they had their name put on a variety of guns that they sold.
Your markings indicate that it was imported into the US by Simpson's Ltd, a gun shop in Galesburg, Ill. Right down the road from me.

Please don't screw up any 10.75x68 brass trying to make 10.75x57s out of it. It is much harder to get, and worth a lot more, than other usable donor brass, such as .35 Whelen.

The 10.75X57 was not a Mannlicher-Schoenauer cartridge.
Yes the 9.5X57 was - 1910 model.

MS did chamber the 10.75X68 in a few rifles (after WW2 ??) but those rifles are extremely rare.

Canuck, I'm thinking of rechambering to 10.75-68 for which I have plenty of brass!
Leonard

quote:

Originally posted by Alberta Canuck:
Please don't screw up any 10.75x68 brass trying to make 10.75x57s out of it. It is much harder to get, and worth a lot more, than other usable donor brass, such as .35 Whelen.

You can't really make 10,75x57 brass out of 10.75x68. Too much difference in case head size.

quote:

Originally posted by lb404:
Canuck, I'm thinking of rechambering to 10.75-68 for which I have plenty of brass!
Leonard

That is not a simple rechamber job. First off, the magazine MAY not be long enough on your rifle. Second, the head diameter is enough larger on the 10.75x68, that you're almost assured that it will require attention of a truly skilled 'smith to be certain of correct and dependable feeding after the rechambering.

It is not impossible, of course; it just may be a lot more expensive and more difficult than you appear to foresee at this point.

Quality Cartridge: http://www.qual-cart.com/ may make the brass. They show it in their .pdf catalog. S40

Isn't the 10.75x57 based off the 8x57? Shouldn't it be easier to simply neck up 8 or 9.3mm brass? I've made a few 8 and 9.3 x57 brass from 270Win in one or two steps and didn't have any trouble with the necks cracking. Am I missing something here?

quote:

Originally posted by gzig5:
Isn't the 10.75x57 based off the 8x57? Shouldn't it be easier to simply neck up 8 or 9.3mm brass? I've made a few 8 and 9.3 x57 brass from 270Win in one or two steps and didn't have any trouble with the necks cracking. Am I missing something here?

You're not missing much, if anything. Yes, it would be easier to neck up some other ?x57 brass. But the loss rate MIGHT be fairly high with even 8m/m brass, depending on its case neck size, neck wall thickness, and temper.

The bigger the inside neck diameter of the case being necked up, the better. Otherwise case neck thickness may become so uneven and/or so thin after necking up as to pose durability and neck tension/bullet pull problems.

The reason I suggested trying some .35 Whelan brass was that the case head diameter is right, and the brass is already opened to accept .358 bullets as it comes. It would have to be shortened before necking up, but that is a lot easier than trying to lengthen 8x57 after necking up. And the necking up process WILL shorten the OAL of the brass made from 8x57.

Whatever...there's more than one way to skin a cat. It's just that some pelts turn out better than others depending on the skinning method used.

If he can get a bunch of 9,3x57 brass, I think necking that up would be the best option easily available.

Any gunsmith worth his salt can quickly rechamber any good Mauser 98 to a 10.75x68 from a 10.75x5, or any 98, FN, or Mod. 70; open the bolt face a little, cut the bolt stop back open up the box a tad, and a little rail work...

Dennis Olson has done a couple of 10.75x68s for me, from 98 Mauser actions, and they worked fine. Made up into 8 to 8.5 lb. rifles with irons, and 9 to 9.5 with a scope, and oh so easy to pack on those long treks in the heat of Africa..recoil is easy on the body, and its a real sho nuff killer with 350 or 400 gr. bullets from Woodleigh, North fork, and Nosler with 400 gr. bullets and the Barnes X in 350 gr. HP will lay a buffalo down right well.

I wish more folks would get excited about the cartridge, all you have to do is try it out, and you will be a believer, but that will probably never come about. Brass has been more available lately..