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{{Short description|Rifle cartridge}}
{{Infobox firearm cartridge
{{Infobox firearm cartridge
| name = .257 Roberts
| name = .257 Roberts
| image = 257 Roberts.JPG | image_size = 300px
| image = 257 Roberts.JPG | image_size = 300px
| caption =
| caption =
| origin = [[United States]]
| origin = United States
| type = Rifle
| type = Rifle
<!-- Service history -->
<!-- Service history -->
Line 13: Line 14:
| design_date = 1920s
| design_date = 1920s
| manufacturer = [[Remington Arms]]
| manufacturer = [[Remington Arms]]
| production_date = 1934-Present
| production_date = 1934–present
| number =
| number =
| variants = .257 Roberts (+P), .257 Roberts Ackley Improved
| variants = .257 Roberts +P, .257 Roberts Ackley Improved
<!-- Specifications -->
<!-- Specifications -->
| is_SI_specs =
| is_SI_specs =
| parent = [[7×57mm Mauser]]
| parent = [[7×57mm Mauser]]
| case_type = rimless bottlenecked
| case_type = Rimless, bottleneck
| bullet = .257
| bullet = .257
| neck = .290
| neck = .290
Line 29: Line 30:
| length = 2.775
| length = 2.775
| rifling = 1-10"
| rifling = 1-10"
| primer = large rifle
| primer = Large rifle
<!-- Ballistic performance -->
<!-- Ballistic performance -->
| is_SI_ballistics =
| is_SI_ballistics =
Line 53: Line 54:
| en5 =
| en5 =
| test_barrel_length = 24
| test_barrel_length = 24
| balsrc = Accurate Powders <ref name=accuratepowders>{{cite web |title=Accurate Powder Reloading Data Guide, 5th ed. |url=http://www.accuratepowder.com/wp-content/uploads/2010/09/WP_LoadSpec_7-2-13.pdf |publisher=Western Powders |accessdate=12 July 2013 |pages=29–30 |archiveurl=https://www.webcitation.org/6I7Uhwej6?url=http://www.accuratepowder.com/wp-content/uploads/2010/09/WP_LoadSpec_7-2-13.pdf |archivedate=2013-07-15 |deadurl=no |df= }}</ref>
| balsrc = Accurate Powders <ref name=accuratepowders>{{cite web |title=Accurate Powder Reloading Data Guide, 5th ed. |url=http://www.accuratepowder.com/wp-content/uploads/2010/09/WP_LoadSpec_7-2-13.pdf |publisher=Western Powders |access-date=12 July 2013 |pages=29–30 |archive-url=https://web.archive.org/web/20131101051706/http://www.accuratepowder.com/wp-content/uploads/2010/09/WP_LoadSpec_7-2-13.pdf |archive-date=2013-11-01 |url-status=live }}</ref>
}}
}}


The '''.257 Roberts''' also known as .257 Bob <ref>https://www.americanrifleman.org/articles/2013/7/19/a-classic-returns-in-257-bob/</ref> is a medium-powered .25 [[caliber]] [[Cartridge (firearms)|cartridge]]. It has been described as the best compromise between the low [[recoil]] and flat [[trajectory]] of smaller calibers such as the [[5 mm caliber|.22]] and [[6 mm caliber|6mm]], and the strong energy but not the strong recoil of larger popular hunting calibers, such as the [[7 mm caliber|7mm]] family and the popular [[.30-06]].<ref name="chuck_subscribe">[http://www.chuckhawks.com/subscribers/rifle_cartridge_page/257Rob.htm The .257 Roberts (.257 Roberts +P) by Chuck Hawks] (membership required)</ref>
The '''.257 Roberts''', also known as '''.257 Bob''',<ref>{{Cite web|url=https://www.americanrifleman.org/articles/2013/7/19/a-classic-returns-in-257-bob/|title=An Official Journal of the NRA &#124; A Classic Returns in .257 Bob}}</ref> is a medium-powered .25 [[caliber]] rifle [[Cartridge (firearms)|cartridge]]. It has been described as the best compromise between the low [[recoil]] and flat [[trajectory]] of smaller calibers such as the [[5 mm caliber|5 mm]] (.22 in) and [[6 mm caliber|6 mm]] (.24 in), and has more energy, but is harder recoiling, similar to larger hunting calibers, such as the [[7 mm caliber|7 mm]] (.28 in) and [[7.62 mm caliber|7.62 mm]] (.30 in).<ref name="chuck_subscribe">[http://www.chuckhawks.com/subscribers/rifle_cartridge_page/257Rob.htm The .257 Roberts (.257 Roberts +P) by Chuck Hawks] (membership required)</ref>

Nominal bullet diameter of the .257 Roberts is .257 inches. The .257 Roberts uses the same caliber bullets as [[.250 Savage]] or the more powerful [[.25-06 Remington]]. Barrel rifling diameter, from which calibers derive their designations, is 0.250 in or 6.35 mm.


==History==
==History==
Many cartridge designers in the 1920s were creating various .25 caliber cartridges. Because of its size, the [[7×57mm Mauser]] case was a common choice, having near the ideal volume capacity for the "quarter-bore" (called this because the .25 caliber is one quarter of an inch) using [[smokeless powder|powders]] available at that time. [[Ned H. Roberts|Ned Roberts]] is usually credited with being the designer for this cartridge idea. Eventually in 1934 [[Remington Arms]] chose to introduce their own commercial version of such a cartridge, and although it wasn't the exact dimensions of the [[Wildcat cartridge|wildcat]] made by Roberts, they called it the .257 Roberts.<ref name="cotw8">{{cite book | last=Barnes | first=Frank C. | editor=McPherson, M.L. | title=Cartridges of the World | edition=8th | origyear=1965 | year=1997 | publisher=DBI Books | pages=64, 91 | isbn=0-87349-178-5}}</ref>
Many cartridge designers in the 1920s were creating various 6.35&nbsp;mm (.25 in) caliber cartridges. Due to the availability of inexpensive Mauser actions, the [[7×57mm Mauser]] case was a common choice, having near ideal volume capacity for the "quarter-bore" (0.25&nbsp;in; 6.35&nbsp;mm) using [[smokeless powder|powders]] available at that time. [[Ned H. Roberts|Ned Roberts]] is usually credited with being the designer for this cartridge. Eventually, in 1934, [[Remington Arms]] chose to introduce their own commercial version of such a cartridge, and although it was not the exact dimensions of the [[Wildcat cartridge|wildcat]] made by Roberts, they called it the ".257 Roberts".<ref name="cotw8">{{cite book | last=Barnes | first=Frank C. | editor=McPherson, M.L. | title=Cartridges of the World | edition=8th | orig-year=1965 | year=1997 | publisher=DBI Books | pages=64, 91 | isbn=0-87349-178-5}}</ref>


From its introduction until the appearance of more popular 6&nbsp;mm cartridges such as [[.243 Winchester]] and [[6mm Remington]], it was a very popular general purpose cartridge.<ref name="chuck_free">[http://www.chuckhawks.com/257Rob.htm The .257 Roberts by Chuck Hawks]</ref> Today, although overshadowed by other cartridges, it lives on with [[bolt-action]] rifles being available from some major manufacturers.
From its introduction until the appearance of 6&nbsp;mm cartridges such as [[.243 Winchester]] and [[6mm Remington]], it was a very popular general purpose cartridge.<ref name="chuck_free">[http://www.chuckhawks.com/257Rob.htm The .257 Roberts by Chuck Hawks]</ref> Today, although surpassed in popularity by other cartridges, it lives on with [[bolt-action]] rifles being available from some major manufacturers.


==Conversion of war-souvenir Japanese Arisaka rifles==
==Conversion of war-souvenir Japanese Arisaka rifles==
Japanese [[Type 38 rifle|Type 38]] [[Arisaka]] rifles brought to the [[United States]] as wartime [[souvenir]]s were sometimes converted by rechambering to utilize more readily available .257 Roberts cartridge cases because commercially produced [[6.5×50mm Arisaka]] cartridges were scarce prior to distribution by [[Norma (company)|Norma Projektilfabrik A/S]]. The neck of the Roberts case would be slightly enlarged to accept [[handloading|handloaded]] 6.5&nbsp;mm bullets. The modified Roberts cases are sometimes known as 6.5×.257 Roberts, although the case [[headstamp]] may still indicate .257 Roberts.<ref>Speer ''Wildcat Rifle Loads'' Speer Products Company (1956) p.35</ref> Neither unmodified .257 Roberts ammunition nor the original 6.5×50mm Arisaka ammunition are suitable for firing in rechambered Arisaka rifles.<ref>Davis, William C., Jr. ''Handloading'' National Rifle Association (1981) {{ISBN|0-935998-34-9}} p.170</ref>
Japanese [[Type 38 rifle|Type 38]] [[Arisaka]] rifles brought to the United States as wartime souvenirs were sometimes converted by rechambering to utilize more readily available .257 Roberts cartridge cases because commercially produced [[6.5×50mm Arisaka]] cartridges were scarce prior to distribution by [[Norma Precision|Norma Projektilfabrik A/S]]. The neck of the Roberts case would be slightly enlarged to accept [[handloading|handloaded]] 6.5&nbsp;mm bullets. The modified Roberts cases are sometimes known as "6.5×.257 Roberts", although the case [[headstamp]] may still indicate .257 Roberts.<ref>Speer ''Wildcat Rifle Loads'' Speer Products Company (1956) p.35</ref> Neither unmodified .257 Roberts ammunition nor the original 6.5×50mm Arisaka ammunition are suitable for firing in rechambered Arisaka rifles.<ref>Davis, William C., Jr. ''Handloading'' National Rifle Association (1981) {{ISBN|0-935998-34-9}} p.170</ref>


==Performance==
==Performance==
{{unreferenced section|date=August 2015}}
{{unreferenced section|date=August 2015}}
With light bullets the .257 produces little recoil and has a flat trajectory suitable for [[varmint hunting]]. With heavier bullets it is capable of taking all but the largest North American game animals. The original factory load for this is very similar to the [[.250-3000 Savage]].
With light bullets, the .257 produces little recoil and has a flat trajectory suitable for [[varmint hunting]]. With heavier bullets it produces more recoil, but is capable of taking all but the largest North American game animals.{{citation needed|date=May 2021}} The original factory load for this is very similar to the [[.250-3000 Savage]].


==Improved cartridges==
==Improved cartridges==
Remington introduced the commercial version of this popular [[Wildcat cartridge|wildcat]] as a low-pressure round. At the time there were many older actions available of questionable strength. With a modern action and handloading, this cartridge is capable of markedly improved performance.<ref name="cotw8"/>
Remington introduced the commercial version of this popular [[Wildcat cartridge|wildcat]] as a low-pressure round. At the time there were many older actions available of questionable strength. With a modern action and handloading, this cartridge is capable of markedly improved performance.<ref name="cotw8"/>


One of the common improvements is called the ''.257 Roberts(+P)'' which has a [[SAAMI]] maximum pressure limit of 58,000 PSI compared to the 54,000 PSI listed for the standard .257 Roberts.<ref>{{cite web |title=SAAMI Velocity & Pressure Data: Centerfire Rifle |url=http://www.saami.org/specifications_and_information/specifications/Velocity_Pressure_CfR.pdf |publisher=SAAMI |page=5 |author=Alan Serven <!-- BOT GENERATED AUTHOR --> |accessdate=2013-07-12 |archiveurl=https://www.webcitation.org/6I7VGrifY?url=http://www.saami.org/specifications_and_information/specifications/Velocity_Pressure_CfR.pdf |archivedate=2013-07-15 |deadurl=yes |df= }}</ref>
One of the common improvements is called the ".257 Roberts +P" which has a [[SAAMI]] maximum pressure limit of {{cvt|58000|psi|MPa}} compared to the {{cvt|54000|psi|MPa}} listed for the standard .257 Roberts. It is also the only rifle cartridge with an official "+P" designation.<ref>{{cite web |title=SAAMI Velocity & Pressure Data: Centerfire Rifle |url=http://www.saami.org/specifications_and_information/specifications/Velocity_Pressure_CfR.pdf |publisher=SAAMI |page=5 |author=Alan Serven <!-- BOT GENERATED AUTHOR --> |access-date=2013-07-12 |archive-url=https://web.archive.org/web/20130702015600/http://saami.org/specifications_and_information/specifications/Velocity_Pressure_CfR.pdf |archive-date=2013-07-02 |url-status=dead }}</ref>


P.O. Ackley said that the .257 Roberts Ackley Improved was probably the most useful all-around cartridge.<ref name="ackley1">{{cite book
[[P.O. Ackley]] said that the .257 Roberts Ackley Improved was probably the most useful all-around cartridge.<ref name="ackley1">{{cite book
| last = Ackley
| last = Ackley
| first = P.O.
| first = P.O.
| title = Handbook for Shooters & Reloaders
| title = Handbook for Shooters & Reloaders
| series = vol I
| series = vol I
| origyear =
| year = 1962
| year = 1962
| publisher = Plaza Publishing
| publisher = Plaza Publishing
| pages =
| isbn = 978-99929-4-881-1
| isbn = 978-99929-4-881-1
}}</ref> The Ackley Improved was a typical change of a steeper shoulder coupled with blown-out sides for more of a straight cartridge, providing greater powder capacity.
}}</ref> Making an Ackley Improved cartridge usually meant modifying the chamber to have a steeper shoulder and blown-out sides to provide greater powder capacity while still allowing factory ammunition to be fired safely.


==Comparison==
==Comparison==
Data below shows sample [[muzzle velocity|muzzle velocities]] and [[muzzle energy|muzzle energies]] for a {{cvt|24|in|cm|order=flip}} test barrel, except .250-3000 Savage, which is for a {{cvt|22|in|cm|order=flip}} test barrel and .257 Weatherby Magnum, which is for a {{cvt|26|in|cm|order=flip}} test barrel.

{| class="wikitable sortable"
{| class="wikitable sortable"
|+Quick .25 caliber comparison chart
|+Quick .25 in (6.35&nbsp;mm) caliber comparison chart
! Cartridge !! Bullet weight <br/>([[gram|g]]) !! Bullet weight <br/>([[Grain (unit)|gr]]) !! Muzzle velocity <br/>([[meters per second|m/s]]) !! Muzzle velocity <br/>([[foot per second|ft/s]]) !! Muzzle energy <br/>([[Joule|J]]) !! Muzzle energy <br/>([[Foot-pound (energy)|ft·lbf]])
! cartridge !! Bullet Weight !! Muzzle Velocity (ft/sec)!! Muzzle Energy (ft·lbf)
|-
|-
| [[.250-3000 Savage]] <ref>{{cite web |title=Nosler Reloading Guide 7, 250-3000 Savage |url=http://www.nosler.com/250-3000-savage |publisher=Nosler |accessdate=12 July 2013 |archiveurl=https://www.webcitation.org/6I7UiP6UX?url=http://www.nosler.com/250-3000-savage |archivedate=2013-07-15 |deadurl=no |df= }}</ref> || 100 || 2911 || 1882
| [[.250-3000 Savage]]<ref>{{cite web |title=Nosler Reloading Guide 7, 250-3000 Savage |url=http://www.nosler.com/250-3000-savage |publisher=Nosler |access-date=12 July 2013 |archive-url=https://web.archive.org/web/20130708042942/http://www.nosler.com/250-3000-savage |archive-date=2013-07-08 |url-status=live }}</ref> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|2911|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|1882|ft.lbf|J|disp=table|abbr=on|order=flip}}
|-
|-
| .257 Roberts <ref name=accuratepowders/> || 100 || 3020 || 2025
| .257 Roberts <ref name=accuratepowders/> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|3020|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|2025|ft.lbf|J|disp=table|abbr=on|order=flip}}
|-
|-
| .257 Roberts (+P) <ref name=accuratepowders/> || 100 || 3090 || 2120
| .257 Roberts +P <ref name=accuratepowders/> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|3090|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|2120|ft.lbf|J|disp=table|abbr=on|order=flip}}
|-
|-
| .257 Roberts Ackley Improved <ref>{{cite web|title=Nosler Reloading Guide 7, 257 Roberts Ackley Improved|url=http://www.nosler.com/257-roberts-ackley-improved|publisher=Nosler|accessdate=12 July 2013}}</ref> || 100 || 3226 || 2311
| .257 Roberts Ackley Improved <ref>{{cite web|title=Nosler Reloading Guide 7, 257 Roberts Ackley Improved|url=http://www.nosler.com/257-roberts-ackley-improved|publisher=Nosler|access-date=12 July 2013}}</ref> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|3226|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|2311|ft.lbf|J|disp=table|abbr=on|order=flip}}
|-
|-
| [[.25 WSSM]] <ref name=accuratepowders/> || 100 || 3313 || 2438
| [[.25 WSSM]]<ref name=accuratepowders/> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|3313|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|2438|ft.lbf|J|disp=table|abbr=on|order=flip}}
|-
|-
| [[.25-06 Remington]] <ref name=accuratepowders/> || 100 || 3324 || 2454
| [[.25-06 Remington]]<ref name=accuratepowders/> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|3324|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|2454|ft.lbf|J|disp=table|abbr=on|order=flip}}
|-
|-
| [[.257 Weatherby Magnum]] <ref name=accuratepowders/> || 100 || 3512 || 2739
| [[.257 Weatherby Magnum]]<ref name=accuratepowders/> || {{cvt|100|gr|g|disp=table|abbr=on|order=flip}} || {{cvt|3512|ft/s|m/s|disp=table|abbr=on|order=flip}} || {{cvt|2739|ft.lbf|J|disp=table|abbr=on|order=flip}}
|}
|}

Data for muzzle velocity and muzzle energy is for a 24" barrel, except .250-3000 Savage which is for a 22" barrel and .257 Weatherby Magnum which is for a 26" barrel.


==See also==
==See also==

Latest revision as of 11:55, 5 September 2023

.257 Roberts
TypeRifle
Place of originUnited States
Production history
DesignerNed Roberts
Designed1920s
ManufacturerRemington Arms
Produced1934–present
Variants.257 Roberts +P, .257 Roberts Ackley Improved
Specifications
Parent case7×57mm Mauser
Case typeRimless, bottleneck
Bullet diameter.257 in (6.5 mm)
Neck diameter.290 in (7.4 mm)
Shoulder diameter.430 in (10.9 mm)
Base diameter.472 in (12.0 mm)
Rim diameter.473 in (12.0 mm)
Case length2.233 in (56.7 mm)
Overall length2.775 in (70.5 mm)
Rifling twist1-10"
Primer typeLarge rifle
Ballistic performance
Bullet mass/type Velocity Energy
75 gr (5 g) HP 3,450 ft/s (1,050 m/s) 1,983 ft⋅lbf (2,689 J)
100 gr (6 g) B-TIP 3,020 ft/s (920 m/s) 2,025 ft⋅lbf (2,746 J)
117 gr (8 g) SPBT 2,840 ft/s (870 m/s) 2,096 ft⋅lbf (2,842 J)
Test barrel length: 24
Source(s): Accurate Powders [1]

The .257 Roberts, also known as .257 Bob,[2] is a medium-powered .25 caliber rifle cartridge. It has been described as the best compromise between the low recoil and flat trajectory of smaller calibers such as the 5 mm (.22 in) and 6 mm (.24 in), and has more energy, but is harder recoiling, similar to larger hunting calibers, such as the 7 mm (.28 in) and 7.62 mm (.30 in).[3]

Nominal bullet diameter of the .257 Roberts is .257 inches. The .257 Roberts uses the same caliber bullets as .250 Savage or the more powerful .25-06 Remington. Barrel rifling diameter, from which calibers derive their designations, is 0.250 in or 6.35 mm.

History[edit]

Many cartridge designers in the 1920s were creating various 6.35 mm (.25 in) caliber cartridges. Due to the availability of inexpensive Mauser actions, the 7×57mm Mauser case was a common choice, having near ideal volume capacity for the "quarter-bore" (0.25 in; 6.35 mm) using powders available at that time. Ned Roberts is usually credited with being the designer for this cartridge. Eventually, in 1934, Remington Arms chose to introduce their own commercial version of such a cartridge, and although it was not the exact dimensions of the wildcat made by Roberts, they called it the ".257 Roberts".[4]

From its introduction until the appearance of 6 mm cartridges such as .243 Winchester and 6mm Remington, it was a very popular general purpose cartridge.[5] Today, although surpassed in popularity by other cartridges, it lives on with bolt-action rifles being available from some major manufacturers.

Conversion of war-souvenir Japanese Arisaka rifles[edit]

Japanese Type 38 Arisaka rifles brought to the United States as wartime souvenirs were sometimes converted by rechambering to utilize more readily available .257 Roberts cartridge cases because commercially produced 6.5×50mm Arisaka cartridges were scarce prior to distribution by Norma Projektilfabrik A/S. The neck of the Roberts case would be slightly enlarged to accept handloaded 6.5 mm bullets. The modified Roberts cases are sometimes known as "6.5×.257 Roberts", although the case headstamp may still indicate .257 Roberts.[6] Neither unmodified .257 Roberts ammunition nor the original 6.5×50mm Arisaka ammunition are suitable for firing in rechambered Arisaka rifles.[7]

Performance[edit]

With light bullets, the .257 produces little recoil and has a flat trajectory suitable for varmint hunting. With heavier bullets it produces more recoil, but is capable of taking all but the largest North American game animals.[citation needed] The original factory load for this is very similar to the .250-3000 Savage.

Improved cartridges[edit]

Remington introduced the commercial version of this popular wildcat as a low-pressure round. At the time there were many older actions available of questionable strength. With a modern action and handloading, this cartridge is capable of markedly improved performance.[4]

One of the common improvements is called the ".257 Roberts +P" which has a SAAMI maximum pressure limit of 58,000 psi (400 MPa) compared to the 54,000 psi (370 MPa) listed for the standard .257 Roberts. It is also the only rifle cartridge with an official "+P" designation.[8]

P.O. Ackley said that the .257 Roberts Ackley Improved was probably the most useful all-around cartridge.[9] Making an Ackley Improved cartridge usually meant modifying the chamber to have a steeper shoulder and blown-out sides to provide greater powder capacity while still allowing factory ammunition to be fired safely.

Comparison[edit]

Data below shows sample muzzle velocities and muzzle energies for a 61 cm (24 in) test barrel, except .250-3000 Savage, which is for a 56 cm (22 in) test barrel and .257 Weatherby Magnum, which is for a 66 cm (26 in) test barrel.

Quick .25 in (6.35 mm) caliber comparison chart
Cartridge Bullet weight
(g)
Bullet weight
(gr)
Muzzle velocity
(m/s)
Muzzle velocity
(ft/s)
Muzzle energy
(J)
Muzzle energy
(ft·lbf)
.250-3000 Savage[10] 6.5 g 100 gr 887 m/s 2,911 ft/s 2,552 J 1,882 ft⋅lbf
.257 Roberts [1] 6.5 g 100 gr 920 m/s 3,020 ft/s 2,746 J 2,025 ft⋅lbf
.257 Roberts +P [1] 6.5 g 100 gr 940 m/s 3,090 ft/s 2,870 J 2,120 ft⋅lbf
.257 Roberts Ackley Improved [11] 6.5 g 100 gr 983 m/s 3,226 ft/s 3,133 J 2,311 ft⋅lbf
.25 WSSM[1] 6.5 g 100 gr 1,010 m/s 3,313 ft/s 3,305 J 2,438 ft⋅lbf
.25-06 Remington[1] 6.5 g 100 gr 1,013 m/s 3,324 ft/s 3,327 J 2,454 ft⋅lbf
.257 Weatherby Magnum[1] 6.5 g 100 gr 1,070 m/s 3,512 ft/s 3,714 J 2,739 ft⋅lbf

See also[edit]

References[edit]

  1. ^ a b c d e f "Accurate Powder Reloading Data Guide, 5th ed" (PDF). Western Powders. pp. 29–30. Archived (PDF) from the original on 2013-11-01. Retrieved 12 July 2013.
  2. ^ "An Official Journal of the NRA | A Classic Returns in .257 Bob".
  3. ^ The .257 Roberts (.257 Roberts +P) by Chuck Hawks (membership required)
  4. ^ a b Barnes, Frank C. (1997) [1965]. McPherson, M.L. (ed.). Cartridges of the World (8th ed.). DBI Books. pp. 64, 91. ISBN 0-87349-178-5.
  5. ^ The .257 Roberts by Chuck Hawks
  6. ^ Speer Wildcat Rifle Loads Speer Products Company (1956) p.35
  7. ^ Davis, William C., Jr. Handloading National Rifle Association (1981) ISBN 0-935998-34-9 p.170
  8. ^ Alan Serven. "SAAMI Velocity & Pressure Data: Centerfire Rifle" (PDF). SAAMI. p. 5. Archived from the original (PDF) on 2013-07-02. Retrieved 2013-07-12.
  9. ^ Ackley, P.O. (1962). Handbook for Shooters & Reloaders. vol I. Plaza Publishing. ISBN 978-99929-4-881-1.
  10. ^ "Nosler Reloading Guide 7, 250-3000 Savage". Nosler. Archived from the original on 2013-07-08. Retrieved 12 July 2013.
  11. ^ "Nosler Reloading Guide 7, 257 Roberts Ackley Improved". Nosler. Retrieved 12 July 2013.

External links[edit]