Home loading for the .275
- Thread starter Stalker62
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Stalker62
Well-Known Member
Smellydog
Well-Known Member
7x57??
Jura
Well-Known Member
7x57 Mauser / 275 Rigby, same cartridge with different names.
Screenshot of Vit reloading data
Stalker62
Well-Known Member
@Jura
I knew that!
Just typed in .275 and didn't think.
I have just purchased some ammunition, and the seller made a 'thing' of saying 'technically' he could not sell it as my FAC shows 7x57.
When you try and explain this 'issue' to the FLD, they will tell you there is not enough space on the computer to type in both options.
Thank you for posting that.
Sinistral
Well-Known Member
Only an ammunition nerd and collector would know this, but these are CIP-registered as seperate cartridges.@Jura
I knew that!
Just typed in .275 and didn't think.
I have just purchased some ammunition, and the seller made a 'thing' of saying 'technically' he could not sell it as my FAC shows 7x57.
When you try and explain this 'issue' to the FLD, they will tell you there is not enough space on the computer to type in both options.
Thank you for posting that.
There are very slight dimensional variations between the two, but the PMax pressure for .275 Rigby is significantly lower.
Hornady currently load them as different products, and in the past so did Kynoch.
| C.I.P. DIMENSIONS 9/2024 | L1 | L2 | L3 | R1Ø | P1Ø | P2Ø | H2Ø | G1Ø | SA° |
| 7 x 57 Mauser (3900 Bar) | 1.728 | 1.866 | 2.235 | .473 | .471 | .429 | .325 | .284 | 20 27' |
| .275 Rigby (3200 Bar) | 1.724 | 1.864 | 2.240 | .475 | .474 | .428 | .324 | .284 | 20 21' |
7x57mm 150 gr ECX™ Hornady International™ - Hornady Manufacturing, Inc
Delivering accuracy and performance for hunters around the world, Hornady International features the new ECX™ (Extreme Copper alloy eXpanding) bullet.
Stalker62
Well-Known Member
I get the minute differences in dimensions, but that seems to be a significant variation in pressure.
Funny thing.
Just to make it more confusing - have seen .275 rifle, that is built on a 1912 7x57 action.
To get down into the weeds, the 1936 dated Kynoch catalogue shows the 140gn .275 Rigby at 18 tons square in for the 140 grain and the 173 grain loads at 2750fps and 2400fps respectively and the 7mm (.276) at 18.5 tons square in for the 140 grain & 16.5 tons a square in for the 173 grain for 2900fps and 2300fps respectively.
The Rigby was introduced as the "high velocity loading" for the 7mm which compared to the original 173 grain military loading it was, it looks like Kynoch just pushed the velocity harder in their 140 grain.
I do have a box of later .275" Rigby by Roberts and it is labelled "For use in Rigby rifles only" but that might just be a marketing ploy.
The Rigby was introduced as the "high velocity loading" for the 7mm which compared to the original 173 grain military loading it was, it looks like Kynoch just pushed the velocity harder in their 140 grain.
I do have a box of later .275" Rigby by Roberts and it is labelled "For use in Rigby rifles only" but that might just be a marketing ploy.
Jura
Well-Known Member
These are labelled 13 Pall Mall by appointment to Her Majesty the Queen. That would be before Paul Roberts got involved with Rigby.
Attachments
Sinistral
Well-Known Member
Filched from a foreign website . . .
The .275 Rigby called .275 High Velocity, was introduced by the British company Rigby for its bolt action rifles in 1907. It is, for all practical purposes, the same as the 7x57mm Mauser, although not completely compatible: the maximum chamber pressure is the same as the original 7x57, but lower than today's standard.
According to the official CIP standards, the 7 x 57 Mauser cartridge case can withstand pressures of up to 390 MPa (56564 psi). In countries regulated by the IPC, each rifle and its cartridge must be tested to 125% of the maximum pressure set by the IPC in order to be certified safe and marketable. In comparison, the American industry association SAAMI specifies a maximum pressure of 46,000 CPU (Copper Units of Pressure). This lower specification is due to the weaker bolts and receivers of the Mauser 93 and 95 rifles, which are still in use.
Current European 7mm cartridges use a bullet with a diameter of 7.24 mm (0.285 inches), while American 7mm cartridges use bullets with a diameter of 7.21 mm (0.284 inches).
Sinistral
Well-Known Member
Yes I have a later incarnation of these as well which are loaded with a Nosler bullet, box date is 1975, I think the cases are Norma, printed on the box is a statementI've got some of those too.
They're comparatively modern (boxer-primed).
" RIGBY .275" HIGH VELOCITY CARTRIDGES FOR RIGBY RIFLES ONLY or those which are specially chambered for them in them WE GUARANTEE THE EXERCISE OF REASONABLE CARE IN LOADING BUT ASSUME NO FURTHER RESPONSIBILITY"
I might have to sacrifice a few in the name of science to get a velocity reading though when you look at the test barrel lengths Kynoch were using back then at 28" for the .275" and 29" for the 7mm the figures today will probably be lower.
Heym SR20
Well-Known Member
The 7x57 ad the 275 Rigby are identical cartridges. Only difference is the name.
Any 7x57 data is the same as any 275 Rigby data. Indeed I have reloaded the 7x57 for several years and I dont think have found data published for the 275.
Interesting stuff!
I have an old (?1970s-80s) Nobel-Glasgow manual, and after the 7x57 Mauser data is says 'Note: reduce maxiumum charge by 2grains when using 1993-96 Mauser'. Tha max loads range from 39.0 of Rifle 2 for a 150gr jacketed bullet to 49.5gr Rifle 0 with 100gr.
I have an old (?1970s-80s) Nobel-Glasgow manual, and after the 7x57 Mauser data is says 'Note: reduce maxiumum charge by 2grains when using 1993-96 Mauser'. Tha max loads range from 39.0 of Rifle 2 for a 150gr jacketed bullet to 49.5gr Rifle 0 with 100gr.
Heym SR20
Well-Known Member
Remember that the 7x57 was one of, if not the earliest “modern” centre fire rifle cartridge from the 1890s. Some of the early bolt action rifles were not that strong, hence the lower pressures of some of the original ammo, and some of the anemic factory loads.
The 275 Rigby High Velocity was Rigby’s own brand. Firstly it was anglicised as we had a little war with the Germans and felt the sting of the 7mm Mauser in the Boer War. And the High Velocity load was a 140 gn bullet at 2750 to 2800 fps.
I have read that some rifles so chambered had a shorter lead for the shorter bullet and a slower twist rate. But Rigby rifles were always semi custom so lots of variation - very much dependent on the customer.
The Kynoch packaging stating for Rigby rifles only was to discourage the use of the higher pressure rounds in old Mauser rifles of uncertain vintage. Certainly in Southern Africa there would have been plenty of old Boer War era rifles of uncertain origin in the hands old old farmers still in use.
Rigby rifles were built on best quality actions.
The 275 Rigby High Velocity was Rigby’s own brand. Firstly it was anglicised as we had a little war with the Germans and felt the sting of the 7mm Mauser in the Boer War. And the High Velocity load was a 140 gn bullet at 2750 to 2800 fps.
I have read that some rifles so chambered had a shorter lead for the shorter bullet and a slower twist rate. But Rigby rifles were always semi custom so lots of variation - very much dependent on the customer.
The Kynoch packaging stating for Rigby rifles only was to discourage the use of the higher pressure rounds in old Mauser rifles of uncertain vintage. Certainly in Southern Africa there would have been plenty of old Boer War era rifles of uncertain origin in the hands old old farmers still in use.
Rigby rifles were built on best quality actions.
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