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Load data for .257 Roberts + .257 | 120gr | Sierra HPBT GameKing

Recommended Powder(s): Accurate 4350, Alliant Reloder-16, Norma URP, ReloadSwiss RS 62, Somchem S365

.257 Roberts + .257 | 120gr | Sierra HPBT GameKing

Load Specifications

(Use the Personalized Load Calculator below to adjust )

Bullet:
.257 | 120gr | Sierra HPBT GameKing
Manufacturer SKU:
1650
Bullet Weight:
120gr | 7.8g
Bullet Diameter:
0.257" | 6.53mm
Bullet Length:
1.170" | 29.7mm
Caliber:
.257 Roberts load data
Case Length (l3):
2.233" | 56.7mm
Cartridge Length (C.O.L.):
2.733" | 69.4mm
Seated Depth:
0.670" | 17.0mm
Shank Seated Depth:
0.525" | 13.3mm
Case Capacity:
56.0 Grains of Water | 3.64 cm³
Primer Size:
Large Rifle (LR)
Max. allowed Pressure:
51488 psi | 3550 bar
LID:
LID_B5799_C241
Last updated:
2025-02-02
Recommended Twist Rate:
1:10 - 1:8

Load data for 122 loads in caliber .257 Roberts with .257 | 120gr | Sierra HPBT GameKing bullet and 61 powders such as Accurate 4350, Alliant Reloder-16, Norma URP, ReloadSwiss RS 62, Somchem S365. The key underlying parameters are shown in the table above.

  • Important Notice: DO NOT go below Minimum Charge or above Maximum Charge unless there are reasons. Since xxlreloading.com has no control over the equipment and components used by the customer and the data used in connection with the website, any responsibility and liability for the results achieved is rejected. Also see our Terms of Service

    Questions regarding the load data: Please read the information in the next tab "Explanations".

  • Muzzle velocity vs. barrel length

    Every 1 inch additional barrel length increases muzzle velocity by approx. 30.3 fps

  • We recommend you limit powder range to relevant brands to speed up re-calculation of results

    Use the Personalized Load Calculator to customize loads to your own specific requirements. Find more details in the help section.

    Our default view only displays powders/loads that fulfill certain criteria: Max pressure of a load <=90% of Max. Standardized Pressure. Fill Rate (Min FR): >80% and <100% for rife loads,  >60% and <100% for pistol loads. Min. Propellant Combustion (Min z): >90% for rifle loads , >80% for pistol/revolver loads. Relax these criteria at your own risk to potentially get more powders shown in the load tables.

    .

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Click on the desired row in the tables below to add a specific load / powder to your Diary and manage there.

Powder
Charge
FR
MaxP
%
V(0)
z
ADI AR 2208
<<locked>>
84%
45847
89%
**51
99%
[ADI AR 2209]*
<<locked>>
96%
45643
89%
**10
94%
Accurate 2700
<<locked>>
85%
46238
90%
**02
96%
Accurate 3100
<<locked>>
97%
39581
77%
**89
96%
Accurate 4350 👍
<<locked>>
91%
45411
88%
**23
99%
Alliant Reloder- TS 15.5
<<locked>>
84%
45919
89%
**74
100%
Alliant Reloder-16 👍
<<locked>>
92%
45759
89%
**53
99%
Alliant Reloder-17
<<locked>>
88%
45687
89%
**79
100%
Alliant Reloder-19
<<locked>>
97%
46151
90%
**26
95%
[Alliant Reloder-22]*
<<locked>>
97%
40596
79%
**61
93%
Alliant Reloder-23
<<locked>>
97%
38508
75%
**28
99%
[Alliant Reloder-25]*
<<locked>>
96%
33475
65%
**10
94%
Alliant Reloder-26
<<locked>>
97%
42482
82%
**82
98%
Hodgdon H380
<<locked>>
83%
45730
89%
**74
98%
Hodgdon H414
<<locked>>
87%
46224
90%
**40
97%
Hodgdon H4350
<<locked>>
93%
46296
90%
**77
96%
Hodgdon Hybrid 100V
<<locked>>
94%
45353
88%
**94
100%
Hodgdon LVR
<<locked>>
89%
45788
89%
**20
98%
Hodgdon Superperformance
<<locked>>
89%
45324
88%
**43
96%
Hodgdon VARGET
<<locked>>
84%
45382
88%
**44
99%
Hodgdon TrailBoss
<<locked>>
96%
33924
66%
**86
100%
IMR 4064
<<locked>>
85%
46166
90%
**48
99%
IMR 4166 Enduron
<<locked>>
85%
45672
89%
**12
96%
IMR 4350
<<locked>>
91%
45992
89%
**67
96%
IMR 4451 Enduron
<<locked>>
86%
45353
88%
**35
96%
IMR 4831
<<locked>>
96%
45339
88%
**97
99%
[IMR 4955 Enduron]*
<<locked>>
97%
44150
86%
**28
92%
Lovex S065
<<locked>>
88%
45368
88%
**44
98%
Lovex S070
<<locked>>
90%
45847
89%
**74
97%
[Lovex S071]*
<<locked>>
97%
33156
64%
**44
93%
[Norma 204]*
<<locked>>
91%
45571
89%
**97
94%
Norma MRP
<<locked>>
97%
42250
82%
**36
95%
Norma URP 👍
<<locked>>
92%
46122
90%
**26
99%
Ramshot Hunter
<<locked>>
92%
46195
90%
**49
98%
[Ramshot Magnum]*
<<locked>>
96%
38464
75%
**89
92%
ReloadSwiss RS 14
<<locked>>
95%
34069
66%
**19
100%
ReloadSwiss RS 50
<<locked>>
83%
45672
89%
**54
97%
ReloadSwiss RS 60
<<locked>>
89%
46311
90%
**02
100%
ReloadSwiss RS 62 👍
<<locked>>
91%
45571
89%
**49
99%
ReloadSwiss RS 70
<<locked>>
92%
45832
89%
**76
98%
Rottweil R 903
<<locked>>
86%
46079
90%
**84
100%
[Rottweil R 904]*
<<locked>>
95%
46325
90%
**74
93%
Rottweil R 905
<<locked>>
97%
44759
87%
**10
95%
Rottweil R 907
<<locked>>
87%
45643
89%
**41
96%
SNPE Vectan SP 11
<<locked>>
85%
45948
89%
**13
100%
SNPE Vectan Tubal 5000
<<locked>>
84%
45368
88%
**56
100%
SNPE Vectan Tubal 7000
<<locked>>
89%
45571
88%
**02
96%
Shooters World Long Rifle
<<locked>>
88%
45368
88%
**44
98%
Somchem S355
<<locked>>
85%
46050
89%
**67
100%
[Somchem S361]*
<<locked>>
94%
45397
88%
**25
92%
Somchem S365 👍
<<locked>>
94%
45382
88%
**56
100%
Somchem S385
<<locked>>
97%
46064
89%
**07
96%
Vihtavuori N135
<<locked>>
86%
45934
89%
**08
100%
Vihtavuori N150
<<locked>>
90%
45223
88%
**28
100%
Vihtavuori N160
<<locked>>
88%
45440
88%
**77
99%
[Vihtavuori N165]*
<<locked>>
97%
38000
74%
**30
93%
Vihtavuori N550
<<locked>>
89%
46311
90%
**26
99%
Vihtavuori N555
<<locked>>
97%
41945
81%
**97
99%
Winchester 6.5 StaBALL
<<locked>>
90%
45469
88%
**64
100%
Winchester 760
<<locked>>
87%
46224
90%
**40
97%
Winchester StaBALL HD
<<locked>>
97%
34040
66%
**28
99%

Max Load - Barrel Length: 23.60''

Powder
Charge
FR
MaxP
%
V(0)
z
ADI AR 2208
<<locked>>
81%
42032
82%
**79
99%
[ADI AR 2209]*
<<locked>>
88%
35592
69%
**90
90%
[Accurate 2700]*
<<locked>>
81%
40437
79%
**90
94%
[Accurate 3100]*
<<locked>>
86%
27760
54%
**06
91%
Accurate 4350
<<locked>>
81%
32416
63%
**41
95%
Alliant Reloder- TS 15.5
<<locked>>
81%
41872
81%
**02
100%
Alliant Reloder-16
<<locked>>
81%
32634
63%
**61
95%
Alliant Reloder-17
<<locked>>
81%
36361
71%
**79
98%
[Alliant Reloder-19]*
<<locked>>
87%
34606
67%
**80
90%
[Alliant Reloder-22]*
<<locked>>
92%
34751
67%
**26
90%
[Alliant Reloder-23]*
<<locked>>
81%
23612
46%
**01
91%
[Alliant Reloder-25]*
<<locked>>
92%
29269
57%
**82
91%
[Alliant Reloder-26]*
<<locked>>
84%
26861
52%
**56
90%
Hodgdon H380
<<locked>>
81%
42714
83%
**12
98%
[Hodgdon H414]*
<<locked>>
81%
37507
73%
**59
94%
[Hodgdon H4350]*
<<locked>>
81%
31705
62%
**52
90%
Hodgdon Hybrid 100V
<<locked>>
81%
29762
58%
**52
96%
Hodgdon LVR
<<locked>>
81%
35389
69%
**97
95%
[Hodgdon Superperformance]*
<<locked>>
81%
33852
66%
**80
91%
Hodgdon VARGET
<<locked>>
81%
41582
81%
**69
99%
Hodgdon TrailBoss
<<locked>>
92%
31981
62%
**50
100%
IMR 4064
<<locked>>
81%
41104
80%
**52
99%
IMR 4166 Enduron
<<locked>>
81%
40886
79%
**20
95%
[IMR 4350]*
<<locked>>
81%
33054
64%
**95
91%
[IMR 4451 Enduron]*
<<locked>>
81%
38943
76%
**03
94%
[IMR 4831]*
<<locked>>
81%
28471
55%
**23
93%
[IMR 4955 Enduron]*
<<locked>>
94%
40509
79%
**46
90%
Lovex S065
<<locked>>
81%
36390
71%
**57
95%
[Lovex S070]*
<<locked>>
81%
34432
67%
**28
93%
[Lovex S071]*
<<locked>>
91%
27340
53%
**90
90%
[Norma 204]*
<<locked>>
84%
35404
69%
**77
90%
[Norma MRP]*
<<locked>>
88%
31531
61%
**67
90%
Norma URP
<<locked>>
81%
32474
63%
**38
95%
[Ramshot Hunter]*
<<locked>>
81%
31749
62%
**18
92%
[Ramshot Magnum]*
<<locked>>
94%
34867
68%
**97
90%
ReloadSwiss RS 14
<<locked>>
87%
30255
59%
**44
100%
ReloadSwiss RS 50
<<locked>>
81%
42873
83%
**92
96%
ReloadSwiss RS 60
<<locked>>
81%
35201
68%
**69
99%
ReloadSwiss RS 62
<<locked>>
81%
32068
62%
**57
95%
[ReloadSwiss RS 70]*
<<locked>>
81%
32024
62%
**54
93%
Rottweil R 903
<<locked>>
81%
39247
76%
**49
99%
[Rottweil R 904]*
<<locked>>
89%
37869
74%
**03
90%
[Rottweil R 905]*
<<locked>>
88%
33997
66%
**67
90%
[Rottweil R 907]*
<<locked>>
81%
37231
72%
**64
93%
SNPE Vectan SP 11
<<locked>>
81%
40277
78%
**98
99%
SNPE Vectan Tubal 5000
<<locked>>
81%
41365
80%
**84
100%
[SNPE Vectan Tubal 7000]*
<<locked>>
81%
35360
69%
**95
93%
Shooters World Long Rifle
<<locked>>
81%
36390
71%
**57
95%
Somchem S355
<<locked>>
81%
40074
78%
**56
99%
[Somchem S361]*
<<locked>>
90%
40669
79%
**39
90%
Somchem S365
<<locked>>
81%
29153
57%
**95
97%
[Somchem S385]*
<<locked>>
86%
31778
62%
**02
90%
Vihtavuori N135
<<locked>>
81%
38856
75%
**84
100%
Vihtavuori N150
<<locked>>
81%
34258
67%
**11
99%
Vihtavuori N160
<<locked>>
81%
35172
68%
**70
96%
[Vihtavuori N165]*
<<locked>>
92%
33228
65%
**15
90%
Vihtavuori N550
<<locked>>
81%
36056
70%
**16
96%
[Vihtavuori N555]*
<<locked>>
81%
25034
49%
**70
92%
Winchester 6.5 StaBALL
<<locked>>
81%
33591
65%
**25
98%
[Winchester 760]*
<<locked>>
81%
37507
73%
**59
94%
[Winchester StaBALL HD]*
<<locked>>
85%
23467
46%
**41
90%

Start Load - Barrel Length: 23.60''

Any powder missing? Then click here.

FR ... fill rate of the cartridge in percent

MaxP ... max. pressure of load in psi or bar

% ... max. pressure of load in percent of the maximum allowed pressure for this caliber 

V(0) ... muzzle velocity in feet per second (fps) or  meters per second (m/s)

z ... powder burnt in percent

[...] *... not dangerous but load has suboptimal powder burnt with possible characteristics such as extensive muzzle flash or inaccurate loads.

[...] ²... fill rate low - you might want to consider using a filler to ensure proper ignition.

[...] ᴾ... possible press load - work up slowly to this load while watching for signs of excessive pressure.

👍  ... recommended powder/load for this caliber and bullet combination based on its ballistic performance.

<<locked>>... you need to buy an access license to unlock the data

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