Load data for .257 Roberts + 100gr Speer Boat-Tail

Based on C.I.P., the max. allowed case length is 2.233 in / 56.72 mm, the max. cartridge length is 2.775 in / 70.49 mm, and the max. allowed pressure is 51,488 PSI / 3,550 bar.

Based on C.I.P., the max. allowed case length is 2.233 in / 56.72 mm, the max. cartridge length is 2.775 in / 70.49 mm, and the max. allowed pressure is 51,488 PSI / 3,550 bar.

Load Specifications

ImperialMetric

Bullet:.257 | 100gr | Boat-Tail

Cartridge:.257 Roberts load data

Case Length (L3):2.233" | 56.7 mm

Cartridge Length (COL/L6):•••

Seated Depth:0.458" | 11.6 mm

Case Capacity:58 gow | 3.76 cm³

Primer Size:Large Rifle (LR)

Max. Pressure (C.I.P.):51,488 psi | 3,550 bar

Barrel Length:24.0" | 610 mm

Min. Twist Rate:1:11.5

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Community Loads for .257 Roberts + 100gr Speer Boat-Tail

Real loads for this combination shared by our community. Charge weights are only fully visible with an active Pro licence.

Charge (gr)	C.O.L.	Barrel Length	Velocity (fps)	Pressure (psi)

41.0 gr	2.770"	—	2795 fps	•••

41.5 gr	2.780"	24.0"	2956 fps	•••

41.3 gr	2.770"	—	2830 fps	•••
•••	2.770"	—	3118 fps	•••

•••	2.770"	—	2821 fps	•••
•••	2.770"	—	3019 fps	•••

•••	2.770"	—	2815 fps	•••
•••	2.770"	—	3065 fps	•••

•••	2.770"	—	2697 fps	•••
•••	2.770"	—	2998 fps	•••

•••	2.770"	—	2932 fps	•••

•••	2.770"	—	2650 fps	•••
•••	2.770"	—	2902 fps	•••

•••	2.770"	—	2910 fps	•••

•••	2.770"	—	2756 fps	•••
•••	2.770"	—	3014 fps	•••

•••	2.770"	—	2878 fps	•••

•••	2.770"	—	2691 fps	•••
•••	2.770"	—	2932 fps	•••

•••	2.770"	—	2883 fps	•••

•••	2.770"	—	2882 fps	•••
•••	2.770"	—	3055 fps	•••

•••	2.770"	—	2712 fps	•••
•••	2.770"	—	2965 fps	•••

•••	2.770"	—	2823 fps	•••
•••	2.770"	—	2838 fps	•••
•••	2.770"	—	3129 fps	•••
•••	2.770"	—	2789 fps	•••
•••	2.770"	—	3062 fps	•••

Charge weights beyond the first rows and all pressure values are only visible with an active Pro licence.