While at the Dallas Safari Club Show this week, I stopped by the Hornady booth and noticed that they will be offering loaded ammo with the 275 Rigby headstamp...and hopefully we'll be able to buy brass in the near future as well.

The 275 Rigby in most cases is a 7x57 Mauser. The bore on a .275 Rigby early on was supposed to be .287 as opposed to .284 with the 7x57. but I have shot so many .275 Rigbys with 7x57 ammo and they all shot well that I really doubt that there is any difference..Perhaps one would get less pressure shooting 7x57s in a true .275 Rigby and more pressure shooting 275 Rigbys in his 7x57, don't know. I did have a friend that shot Woodleigh .275 Rigby (.287 bullets) in his super nice old Mauser Mauser 7x57 for years, at least until I brought to his attention.

My 7x57 G33-40 Mauser custom is marked .275 Rigby, but I shoot 7x57 ammo in it exclusively because it has a Lothar Walthar barrel and they don't make a .287 barrel, mine mics .284 btw. I'll buy some of that brass for sure.

Thanks for the 'heads up' , I don't expect to see any of that brass on this side of the Pond any time soon, but it will be a small challenge to grapple with in due time. I'm using Norma 7x57 brass up to now, which once fire formed conforms to the 275 Rigby chamber. I am led to understand that there is a very slight headspace difference between the two calibres, which in reality makes no difference.

Awesome!!!!!!!!!


I will be able to take my 275 Rigby to Africa now!!!!!!!!!!

The main difference is not in the case, its in the bullet, the case will take care of itself once fired either way...

A .275 Rigby has a .287 bore and a 7x57 has a .284 bore, so shooting 7x57 in a 275 Rigby is fine, but may or may not shoot accurately, have to test them to know that..

Shooting a .287 bullet in a .284 bore is a snug fit for sure but reportedly not a dangerous practice and I suspect that is correct. You can divide that three thousands by 4 as you have 4 sides to a bullet and it comes out to not much. So again you can shoot either way..but you need to test them for accuracy, but that should be down with any load, so there ya go.

I just finished a nice custom 7x57 with a Lothar Walthar barrel and I had on hand a beautifully engraved color case hardened bottom metal marked 275 Rigby, so I marked the barrel .275 Rigby because of that and a bit of nostalgia grabbed me as usual..Hopefully I can get some to that ammo or brass marked .275 Rigby, but if not I'm good to go and its certainly a tack driver with all bullets and loads tested and all loads shoot to the same POI, God bless Lothar Walthar, they just seem to do that.

Interesting, I didn't know about the .004 difference. I thought they were the same, just different name.

Dr. Lou,
It's .003 btw...As usual the Germans over engineered things and created havoc among the masses!

Of note Woodleigh lists both .287 and .284 bullets..

Bottom line is that it is no issue, but interesting and educational conversation.

quote:

Originally posted by Atkinson:
Dr. Lou,
It's .003 btw...As usual the Germans over engineered things and created havoc among the masses!

Of note Woodleigh lists both .287 and .284 bullets..

Bottom line is that it is no issue, but interesting and educational conversation.

Oops!

I've never heard of .287 diameter bullets, but leading new things is what I enjoy most about lurking about AR.

Mr. Atkinson. The difference between the 2 diameters is .003. However, wouldn't the additional pressure on the sidewall of the bullet translate to .0015 or essentially diameter oversize/2?

quote:

Originally posted by Atkinson:
The main difference is not in the case, its in the bullet, the case will take care of itself once fired either way...


Shooting a .287 bullet in a .284 bore is a snug fit for sure but reportedly not a dangerous practice and I suspect that is correct. You can divide that three thousands by 4 as you have 4 sides to a bullet and it comes out to not much. So again you can shoot either way..but you need to test them for accuracy, but that should be down with any load, so there ya go.

.

C.I.P.

"7 x 57" country of origin: Germany

"275 H. V. Rigby" country of origin: Great Britain

"275 Belted N. E." country of origin: USA

There are separate specification pages for each of these with cartridge, chamber, bullet, and barrel specs.

Only slight differences exist between the 7x57 and 275 HV Rigby, but they are two distincltly different cartridges per C.I.P.

Cartridge Name: ........... 7x57 ...................... 275 HV Rigby ..................... 275 Belted NE
Cartridge Maximums:
cartridge length: .......... 57.00mm ................... 56.90mm .......................... 63.50mm (2.5"-Americanish/Remingtonish)
rim thickness: ............. 1.15mm .................... 1.09mm ........................... 1.27mm
belt diameter: ............. n/a ....................... n/a .............................. 13.56mm
case head diameter: ........ 12.01mm ................... 12.04mm .......................... 13.03mm (above the belt)
shoulder diameter: ......... 10.92mm ................... 10.87mm .......................... 11.43mm
neck-1 diameter: ........... 8.25mm .................... 8.23mm ........................... 8.25mm
neck-2 diameter: ........... 8.25mm .................... 8.23mm ........................... 8.25mm
base to shoulder length: ... 43.84mm ................... 43.79mm .......................... 53.34mm

Projectile Diameter ........ 7.25mm (.2854")............ 7.21mm (.2839")................... 7.29mm (.2870")

Max. Av. Pressure: ......... 3900 bar (~56,550psi)...... 3200 bar (~46,400psi)............. 4150 bar (~60,175psi)

Barrel Minimum Rifling Diameters:
bore diameter: ............. 6.98mm .................... 6.97mm ........................... 7.04mm
groove diameter: ........... 7.24mm .................... 7.25mm ........................... 7.28mm

Twist Rate Standard: ....... 220.00mm (1:8.66")......... 203.00mm (1:7.99")................ 255.00mm (1:10.03")

ALF,

Thanks for that history.
CIP has an impossible task in sorting it all out for hundreds of chamberings.
They are at least a place to hang some chosen specs from a snapshot of submissions in 1984, June 14.
The latest update I have is dated 2002, May 15.
There is still lots of weird stuff in that tabulation by CIP.

As for the "275 High Velocity Rigby" nomenclature:
"HV" was certainly not by comparison to the 7x57 Mauser standard load, which was a higher pressure loading.

Since Rigby has been so closely associated with Mauser since the 1890s, one wonders why they had to come up with any kind of sales gimmick at all?
Was it just not cricket to shoot a Kraut chambering after WWI? Political correctness?
Good to see Rigby now reclaiming the Mauser association full steam ahead,
with two of the London Rigby Rifles made in 2013 (a .375 H&H and a .416 Rigby) using Mauser advertising on the left side of the action:

Buy one of those "limited edition" Ruger No 1 stamped 275 Rigby. Do a chamber cast and bingo you have a 7x57. There may be some older Rigby made rifles that have a different chamber but anyone passing off a current production rifle as a 275 Rigby is conning the suckers. BTW that 275 Hornady stuff works fine in my No 1, 1950s FN and old Husky all of which are marked 7x57.
Sorta like thinking there is a difference between a an old model 70 marked 30 US Govt 1906 and a new one marked 30-06.

Well when in doubt, go to Wiki:

<The Spanish military adopted a new Mauser rifle design in 1893. This took a smokeless powder centerfire cartridge with a bullet with a nominal diameter of 7 mm (0.285 in), and a case length of 57 mm - hence the names "7×57mm Mauser" and "7×57mm Spanish Mauser".

European 7 mm cartridges all have 7.24 mm (0.285 in) grooves diameter. American 7 mm cartridges have 7.21 mm (0.284 in) grooves diameter.>

The only commercial cartridges that I am aware of using .287 bullets are the 275 H&H and 280 Ross. A quick trip to my cartridge collection with a mike confirmed that. (see Wiki).

The contrary British and their odd ways ! a 244 H&H uses a .240 bullet, also an oddball.

So there are no 7x57s or 275 Rigbys rifles or ammo purposely made with .287 barrels/ammo.

The difference between .284 and .285 is a non event. I shoot .224 bullets in all my .223 Hornets and have yet to have any issues.

Again Wiki says:

<Rigby landmarks include the 1897 introduction of the .450 calibre Nitro Express Double Rifle; the 1899 production of the Rigby .275 calibre (7x57 Mauser) built on the Mauser action and the Rigby .350 calibre Express Rifle; and the 1900 introduction of the .350 Mauser actioned rifles.>

<The 7×57mm cartridge, also known as the 7 mm Mauser, 7×57mm Mauser, 7 mm Spanish Mauser in the USA and .275 Rigby in the United Kingdom, was developed by Paul Mauser of the Mauser company in 1892 and adopted as a military cartridge by Spain in 1893.>

I can easily believe a heavily shot 1893 Mauser might well slug at .287 but that was not the spec.

As a side note a lot of German .318 Mausers were converted to shoot the .323 spritzer by just deepening the grooves, the bore was untouched.
Many 8x60 Mausers were made with .318 barrels and the ammo was .323. Theory was it would shoot flatter. (see Speed book).

Insofar as banded mono metal bullets go, the myth of high pressure will just not die. Less bearing area promotes lower pressure and higher velocity.
The proof sits in my gun safe, A 30" barreled Browning High Wall with an odd 1 in 13 twist that will shoot the new 80 gr TTSX @4000 fps. Deadly and sub moa 5 shot groups.

Finally the Hornady 275 Rigby ammo is nice to put on the shelf with you rifle so marked, but in none of mine does it shoot as well as Privi 7x57 and costs almost 3 times as much.

Wiki is a good source and well footnoted unlike your photos.

You pull one of those bullets (I note it does not say 275 Rigby which is the thread's subject) and you will probably find, as with many European long round nose soft point or FMJ bullets or that era, the LARGEST diameter could well be 7.25 mm, but that is not the "bullet diameter". We had an excellent home grown example here in the old 160 gr Hornady 6.5 softpoint which was tapered from base to nose to fit the leade of the Swedish Mauser (many of which were made by Mauser).

In any case your posting if off the thread topic. When you come up with a Rigby made 275 Rigby that slugs .287 or British factory ammo of that era in 275 Rigby that has .287 bullets in it, let us know.

Oh and BTW 7.5 mm converts to .28543" NOT .287
(you can find that under metric conversion on Wiki).

While it is out of print and very expensive, you may want to hunt down a copy of Mauser: Original Oberndorf Sporting Rifles by Jon Speed.

He is a real expert and knowing my love of Springfields, sold me the Mauser Werke original plans for Mauser to build sporting rifles on 1903 NRA Sporter barreled actions. The rifle shown below was constructed from these plans at no small expense but as the original idea was spearheaded by Col Whelen and AF Stoeger, I found it a rewarding project.



A small portion of the original full size plan which I sell copies of on Amazon.

quote:

Originally posted by ALF:
Was there ever such a thing as a 275 Rigby ?

To the best of my knowledge there has NEVER been;

- a Rigby rifle catalogued as being chambered in '.275 Rigby'
- An orig. Rigby rifle marked '.275 Rigby' [nor a Gibbs or Westley Richards marked '.275 Rigby']
- British or German cartridges[or boxes] stamped or labelled, '.275 Rigby'

Rigby did however catalogue and sell bolt rifles chambered in '.275'

The idea of marking a rifle & brass with '.275 Rigby' is purely modern imagination-with no historical basis
of such a thing ever having being done by the orig. period manufacturers of .275 bore rifles and ammunition.

As we can see, even the Rigby over labelled Kynoch rounds, do not say '.275 Rigby'.
Instead, it simply refers to them as being suitable for a - Rigby Magazine Rifle- in .275 bore.




..and orig. 140gn SP loads do not say '.275 Rigby' on the case or box:
instead, they are designated/specified as .275 bore for the - Rigby Special High Velocity Rifle-,
that being the No:2 catalogued rifle, [i.e.: regulated for the 140gn HV load]

quote:

Originally posted by ALF:


Then a very "new" Brno in 7x57, this is a short lived effort on the part of the Brno factory to reproduce their rifles of former glory. This is a refurbished Brno 98 VZ24 Mauser in 7x57.

Very nice! Are there any to be had?

It might seem stupid to chime in after ALF's lecture, and I am not arguing, but here I was all along living under the impression that the name .275 Rigby orignated when Rigby loaded the 7x57 With 140 grs bullets...? Did ever Mauser load the 7x57 With lighter bullets?

ALF thanks for proving my point with all your data and photographs.

I just hope we can all agree that the 275 "Rigby" designated rifles were not made for a .287 bullet, the old heavy 7x57 bullets were tapered (like the 6.5 160 Hornady I cited), Mauser did not produce 7x57 rifles with a .287 bore, the limited production Ruger No. 1s were in reality the same chamber as their other No. 1s marked 7x57 and that 7.25 mm is NOT .287.

Finally the only "7mm" rifles that were made for a .287 bullet were the 275 H&H and the 280 Ross.

Those are the facts as my computer, library and ammo collection tell me. Nothing I have seen on this thread, including all the very nice photos, have made me alter my conclusions.

Atitkinson's post of 1/17


The main difference is not in the case, its in the bullet, the case will take care of itself once fired either way... A .275 Rigby has a .287 bore and a 7x57 has a .284 bore, so shooting 7x57 in a 275 Rigby is fine, but may or may not shoot accurately, have to test them to know that.. A .275 Rigby has a .287 bore and a 7x57 has a .284 bore, so shooting 7x57 in a 275 Rigby is fine, but may or may not shoot accurately, have to test them to know that..

my post of 1/24:
…. the only "7mm" rifles made for a .287 bullet were the 275 H&H and the 280 Ross.
Have each in my ammo collection and they mike .287. The H&H is Western and the Ross Dominion.

So I'm still curious.....what is the groove diameter of...

the .275 Rigby

the 7x57 Mauser

I'm a little slow here..sorry.

Well it really depends who rifled the barrel. In the days of cut rifling, the cutter could be set to make the grooves different depths.

An example is when Germany took their .318 bored 8X57 military rifles and recut the grooves deeper so they could shoot the .323 spitzer bullets.

There really are no contemporary drilled bore and cut rifled rifles made except on a custom basis.

If you google 275 Rigby rifles for sale, there are quite a few out there, mostly close to 100 years old. You would have to slug each bore to know what the bore and groove diameter is.

Insofar as I know the only recent mass produced rifles marked 275 Rigby were the Lipsey Ruger No. 1As. They were just a gimmick as a chamber cast will show the are the same barrels put on 1A 7x57, just stamped differently. The Hornady ammo headstamped 275 Rigby is exactly the same as 7X57 and either will chamber and fire in either rifle.

here's the official specs for the 7x57:

http://www.saami.org/pubresour...fle/7mm%20Mauser.pdf

If you have any old rifle, slugging the bore checking the headspace and doing a chamber cast is always prudent.

If you are building or buying a mass produced post world war II marked 7x57 or 275 Rigby you can be almost 100% sure they are 7x57s.

The 275 has a higher "cool factor" among some people, but for the hunter it means nothing.

quote:

Originally posted by Sledge:
So I'm still curious.....what is the groove diameter of...

the .275 Rigby

the 7x57 Mauser

'
CIP spec. will put 7x57 at .285" ...Rigby '.275 bore' would be the same.
Mauser barrels were orig. lapped to the spec. adopted later by CIP.
-Alf should be able to confirm such.

excellent info--thanks for all that Alf