Load data for .257 Roberts + 120gr 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 | 120gr | Boat-Tail

Cartridge:.257 Roberts load data

Case Length (L3):2.233" | 56.7 mm

Cartridge Length (COL/L6):•••

Seated Depth:0.603" | 15.3 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:1:10.5

Get PRO license to unlock all data and calculators

Community Loads for .257 Roberts + 120gr 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)

38.0 gr	2.770"	—	2252 fps	•••
42.0 gr	2.770"	—	2485 fps	•••

38.6 gr	2.770"	—	2634 fps	•••
•••	2.770"	24.0"	2832 fps	•••
•••	2.770"	—	2884 fps	•••

•••	2.770"	—	2819 fps	•••

•••	2.770"	—	2441 fps	•••
•••	2.770"	—	2680 fps	•••

•••	2.770"	—	2332 fps	•••
•••	2.770"	24.0"	2578 fps	•••

•••	2.770"	—	2526 fps	•••
•••	2.770"	—	2794 fps	•••

•••	2.770"	—	2571 fps	•••
•••	2.770"	—	2810 fps	•••

•••	2.770"	—	2743 fps	•••

•••	2.770"	—	2541 fps	•••
•••	2.770"	—	2770 fps	•••

•••	2.770"	—	2670 fps	•••

•••	2.770"	—	2536 fps	•••
•••	2.770"	—	2762 fps	•••

•••	2.770"	—	2571 fps	•••
•••	2.770"	—	2810 fps	•••

•••	2.770"	—	2362 fps	•••
•••	2.770"	—	2685 fps	•••
•••	2.770"	—	2617 fps	•••

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