Since the bore diameter of the 275 is not 284 it's actually 287-288.

So why do so many people continue to mis-mark the cartridge on newly built rifles?

There is .005 difference between the J and S bored 8mm's and we mark them correctly.

So why do people still do this?

nostalgia

Simple answer, nostalgia. Longer answer, my understanding is that the British frequently named their cartridges by land diameter as opposed to groove or bullet diameter.

quote:

Originally posted by MJines:
Simple answer, nostalgia. Longer answer, my understanding is that the British frequently named their cartridges by land diameter as opposed to groove or bullet diameter.

The only real difference is in the leade/throat. The .275 was designed with 145's in mind and is throated accordingly. The 7x57's throat was set up for the longer 175.

Both have bores of .275" and lands of .285".

BWW you are confusing the .275 H&H and .280 Ross which used .287"/.288" bullets.

Yeah, it is the same thing in every way; when Rigby short throated them for the 140 grainers, the rifles were marked as such. When not marked, they are throated for 175s, like the 7mm Mauser. Not sure how you got the idea that the groove dias were different. Remember, Mauser was selling stuff they already made, to Rugby.

I have actually seen it written in the 1900's-1920's as .287-.288 same as the Ross.

I'll see if I can find the book.

Since it is English and like many old nitro cartridges the designation does not need to make sense, e.g. 404 Jeffery - what's .404 about it? Of course it is from the German cartridge but same thing like the 7x57..maybe lost in translation

quote:

Originally posted by Big Wonderful Wyoming:
Since the bore diameter of the 275 is not 284 it's actually 287-288.

So why do so many people continue to mis-mark the cartridge on newly built rifles?

There is .005 difference between the J and S bored 8mm's and we mark them correctly.

So why do people still do this?

I think the 8mm difference is discussed in Pierre van der Walt's excellent book "African dangerous Game Cartridges", will try and look it up later on my Kindle.

I am sure many Mauser experts here will know.


Best wishes, Chris

quote:

Originally posted by z1r:
The only real difference is in the leade/throat. The .275 was designed with 145's in mind and is throated accordingly. The 7x57's throat was set up for the longer 175.

sorry but some correction is needed.

The technical difference between a John-Rigby & Co. Mauser in .275 bore and 7x57,
was not the throat, but the different sight regulation for the two different loadings (140gn vs 173gn),
- chamber & throat measures were identical(7mm Mauser spec.) in both No:1 and No:2 catalogue rifles.

The Number 2 is the reference Rigby used to identify rifles regulated for .275 Rigby Rimless 140gn High Velocity.

Bells Mauser was marked .275, yet he used DWM 7x57 173gn.


Rifle 1 (1910) No:2 .275 for 140gn.

Rifle 2 (1910) No:2 .275 for 140gn.

Rifle 3 (1911) No.2 .275 with sight for 173gn.

Rifle 4 (1912) No:2 .275 with sight for 173gn.

Rifle 5 (1922) No:2 .275 with sight for 173gn.

Rifle 6 (1923) No:1 specifically built for 173gn.


To complicate things regarding bore & groove dia. for .275 Rigby and 7x57
It is typically stated as .275' and .285' respectively for 7x57.
Yet, GS-custom bullets, who are very particular about precisely matching their bullets to ones bore,
actually make different dia. bullets for the .275 Rigby vs 7x57.

The 7x57/.275 Rigby was also known as the, .275 Cervorum and the .275 Thomas Bland.

George Gibbs and Westley-Richards also offered mauser rifles in .275

The original Rigby No:2, .275 marked rifles,..were first sold with 7mm marked Eley ammunition.
The commercial Kynoch hunting ammunition was also marked 7mm.
Rigby would place its own '.275 bore' branded label, over the Kynoch boxes.

The .275 reamer that most make today complies with CIP specs unless special ordered. CIP specs the shorter leade for the 275 H. V. Rigby as they call it.

The Rigby model 1 was regulated for 175 grain loads, the number 2 regulated for 140 grain loads. The number 3 light weight was a smaller rifle with shorter 21" barrel and could be ordered regulated for either the standard or HV load.

So, the way many folks do these days is chamber using a 7x57 reamer if heavy bullets are to be used or use the .275 HV reamer if lighter bullets are to be used.

Set it up the way you want and mark the rifle accordingly.

z1r is right on the money.

Here in Oz if you order a 7x57 reamer from the USA it comes short throated. Imported euro barrels (eg Lothar Walther) pre-chambered for the 7x57 come long throated.

I also used to believe the .275 Rigby was specifically for the 140 load, however a very detailed thread on Nitro Express Forum explained the differences exactly as per z1r's post here.

quote:

Originally posted by z1r:
The Rigby model 1 was regulated for 175 grain loads,
the number 2 regulated for 140 grain loads.
The number 3 light weight was a smaller rifle with shorter 21" barrel and could be ordered regulated for either the standard or HV load.

Customer could also request a No:2 .275, - with extra rear sight arrangement, to accommodate alternative use of 173gn.
Having both a Peep and V-notch set-up, was not uncommon on Rigbys.

Other Rigby options included take-down version .275, including switch barrels of same chambering.
making possible to have one barrel regulated for 140gn, the other for 173gn.

quote:

CIP specs the shorter leade for the 275 H. V. Rigby

Original Rigby .275 bore mausers shoot the shorter 140gn length quiet well, despite a Mauser spec. throat.
Just seems strange a person would go to all the trouble of choosing a nostalgic .275, then build it in a way,
thats not well suited to also firing any regular commercially available 7mm mauser ammunition.
Personally,a short throat .275/7x57 chamber in a StdM98 seems odd, in a SA-M70 I could better understand it.
For some,it could just be about the 'cool' factor of having a .275 marked rifle & not about any need or desire
to have authentic .275 throat specs.
That said, a person is free to throat their .275 marked custom rifle anyway they so please.

One can butter their toast or eat it dry too.

As far as I'm concerned the only way to chamber a 275 or 7x57 is like the Brno mods. 21 and 22..I have done all my 7x57 that way and with the use of H414 you can duplicate the 280 Rem with ease and less pressure..It, in fact, is another way of Improving the caliber but without changing the case demensions...I can seat a 175 gr. bullet half way to the cannalure. I can also get great accuracy with the 130 gr. Speer at 3150 FPS...I can use up to 8 grs. more H414 than most reloading books, but reloading books are also allowing for cheap mausers...bullet jump causing poor accuracy is something that I have never encountered, I have come to the conclusion that its a rumor or bad barrels...I have built a hell of a lot of 7x57 using the Bruno specs and they all shoot 130 to 175 gr. bullets equally well..it requires a 30-06 length magazine btw.

I have two customs on hand as we speak and they are shooting great. I use Lothar Walthar barrels and I have also owned many Brno mod. 21s and 22s and never owned one that didn't shoot really well, and shot others that I didn't own and they have all shot great..Some I mark 275 Rigby, some 7x57...The chamber reamers used show to be exactly the same as the chamber casts I have taken on a Rigby 275, and all Brnos and 7x57s...

I think its safe to say they are indeed the same caliber, and safe to shoot with both ammo and or rifle markings, keeping in mind that we can do the same with any caliber as to throat length, free bore, etc. That changes specs but changes nada!

Trax is dead on with his post.

z1r,

what sir? No Peach Butter on it?

Barbaric...

Kynoch could be contracted to produce rounds to ones prefered specifications, But I don't know of them producing
a deeper seated[shorter OAL] 173gn load, specifically for John Rigby & Co.

To my knowledge:
- Kynoch 173gn are about same oaL as DWM 173gn.
- Kynoch 173gn are about same oaL as Kynoch 7mm-140gn pointed solid.
- DWM (pointed) solids are about same oaL as Kynoch 140gn pointed solid.
- The only shorter(OAL) Kynoch 7mm/.275 bore rounds, were 140gn soft-points, avail. in both pointed and RN.


Kynoch 173gn and 140gn, solids


Kynoch 7mm softs:


DWM 173gn:



DWM pointed solid:

I won't be shooting any old Kynoch or other 19th century ammo in my marked 275 Rigby, just WW cases, premium bullets, and Fed 210s..

Its marked 275 Rigby because I was gifted with a case hardened engraved bottom metal marked .275 Rigby so had the LW fwt. barrel marked to match.

Nostalgia, is wonderful, I feel sorry for folks that don't enjoy it..

Handloading the 7x57 is the way to go - there are so many good options today.

Santa Claus

Forget checking van der Walt's book, he starts at the 9,3x62mm cartridge.

It is an excellent read, although sometimes difficult to wade thru his envy, masked with disdain, for most things American. He considers us backward for our refusal, by 1935, to adopt all British/European cartridges as superior to our own. I consider the word "pragmatic" to be beyond him in this regard.

It is however, a noteworthy compilation of data from reloading manuals worldwide, interspersed with numerous anecdotal material and many excellent photographs.

Rich
JMHO