257 Roberts +P

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Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet length will alter net case capacity,  pressure and velocity. Primer selection is specific and primer types are not interchangeable. These are maximum loads in my firearms and may be excessive in others. All loads should be reduced by 5% as a starting point for development where cartridges have greater than 40 grains in capacity and 10% for cartridges with less than 40 grain capacity following safe handloading practices as represented in established mainstream reloading manuals. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.

Cartridge
257 Roberts +P
Firearm Ruger No.1
Barrel Length 20″
Min – Max Case Length 2.233″ +0.0″/-0.020″
Min – Max Cartridge Overall Length 2.620″ – 2.780″
Primer CCI 200 – Large Rifle
Bullet Diameter 0.258″ +0.0″/-0.003″
Reloading Dies Lee Precision

 

Bullet Type  Bullet Weight
Grains
Net H2O
Grains
Capacity
COL” Powder Type Powder Charge
Grains
Muzzle Velocity
fps
Muzzle Energy
ft/lbs
Hornady FP 60 53.2 2.535 2400 15.0 2163 623
Hornady FP 60 53.2 2.535 TrailBoss 11.0 1899 481
Hornady FP 60 53.2 2.535 Varget 47.0 3686 1811
Sierra Varminter 75 47.0 2.700 IMR4064
44.0 3481 2018
Sierra Varminter 75 47.0 2.700 H414 51.0 3521 2065
Sierra Varminter 75 47.0 2.700 Win 760
50.0 3517 2060
Barnes TSXFB 115 47.3 2.780 Re 19 46.0 2768
1957
Barnes TSXFB 115 47.3 2.780 Hybrid 100V
46.0 2832 2049
Barnes TSXFB 115 47.3 2.780 Norma MRP 47.0 2824 2037
Sierra SP 117 49.1 2.775 Re 17 43.5 2811 2053
Sierra SP 117 49.1 2.775 IMR 7828 SSC
48.0 2830 2081
Sierra SP 117 49.1 2.775 Norma MRP 48.0 2813 2056
Hornady BTSP 117 48.7 2.780 Re 17 44.0 2819 2065
Hornady BTSP 117 48.7 2.780 IMR 4831 46.0 2795 2030
Hornady BTSP 117 48.7 2.780 Norma 204 45.0 2796 2031
Nosler Partition 120 47.8 2.750 IMR 4350 44.0 2799 2088
Nosler Partition 120 47.8 2.750 IMR 7828SSC 47.0 2792 2078
Nosler Partition 120 47.8 2.750 Norma MRP 47.5 2771 2046
Speer SPBT
120
48.6
2.770
Re19 46.0 2794  2081
 Speer SPBT  120  48.6  2.770 IMR 4831 45.5 2800  2091
 Speer SPBT  120  48.6 2.770
Norma MRP 45.5 2787  2070
Speer Grand Slam 120 48.9 2.780 Re19 46.0 2798 2087
Speer Grand Slam 120 48.9 2.780 IMR 4831 44.5 2762 2033
Speer Grand Slam 120 48.9 2.780 IMR7828SSC 47.0 2759 2029
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