Load data for .256 Mag. Gibbs + .257 | 90gr | Sierra Blitzking BT

Recommended Powder(s): ReloadSwiss RS 52, ReloadSwiss RS 60, Somchem S365

Load Specifications

(Use the Personalized Load Calculator below to adjust )

Bullet:	.257 \| 90gr \| Sierra Blitzking BT
Bullet Weight:	90gr \| 5.8g
Bullet Diameter:	0.257" \| 6.53mm
Bullet Length:	1.063" \| 27.0mm
Caliber:	.256 Mag. Gibbs load data
Case Length (l3):	2.173" \| 55.2mm
Cartridge Length (C.O.L.):	2.964" \| 75.3mm
Seated Depth:	0.272" \| 6.9mm
Shank Seated Depth:	0.122" \| 3.1mm
Case Capacity:	56.0 Grains of Water \| 3.64 cm³
Primer Size:	Large Rifle (LR)
Max. allowed Pressure:	49313 psi \| 3400 bar
LID:	LID_B5790_C231
Last updated:	2025-01-01
Recommended Twist Rate:	1:10 - 1:8

Load data for 114 loads in caliber .256 Mag. Gibbs with .257 | 90gr | Sierra Blitzking BT bullet and 57 powders such as ReloadSwiss RS 52, ReloadSwiss RS 60, 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".
A load must fulfill certain criteria to be listed in the default view below - see "powder criteria to fulfill to be listed".

Our load data might deviate from other sources - see the "most common reasons for deviations".

All loads are based on the bullet and case dimensions shown under "Load Specifications" - see "reloading suggestions" if you deviate.

You can set your specifications in the "Personalized Load Calculator".

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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.
Case Length (Inch)
Case Length (mm)
CaseCapacity (GoW)
Min z (%)
Min FR (%)
Max FR*
Barrel Length (Inch)
Barrel Length (cm)
Safety Buffer (%)
.

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>>	86%	43613	88%	**02	97%
[Accurate 2700]*	<<locked>>	88%	43903	89%	**27	91%
Accurate 4064	<<locked>>	86%	44150	90%	**38	100%
Accurate 4350	<<locked>>	95%	44005	89%	**91	96%
Alliant Reloder- TS 15.5	<<locked>>	87%	43714	89%	**41	98%
Alliant Reloder-15	<<locked>>	85%	44019	89%	**48	97%
Alliant Reloder-16	<<locked>>	95%	44338	90%	**17	96%
Alliant Reloder-17	<<locked>>	91%	43656	89%	**33	98%
[Alliant Reloder-23]*	<<locked>>	97%	32764	66%	**25	93%
Hodgdon CFE223	<<locked>>	86%	44092	89%	**77	96%
Hodgdon H380	<<locked>>	86%	43511	88%	**28	95%
[Hodgdon H414]*	<<locked>>	90%	44019	89%	**81	93%
[Hodgdon H4350]*	<<locked>>	96%	43816	89%	**02	91%
Hodgdon Hybrid 100V	<<locked>>	97%	42612	86%	**35	98%
Hodgdon LVR	<<locked>>	92%	44135	89%	**84	95%
Hodgdon VARGET	<<locked>>	87%	43961	89%	**09	97%
Hodgdon TrailBoss	<<locked>>	96%	33040	67%	**85	100%
IMR 3031	<<locked>>	85%	44179	90%	**71	100%
IMR 4064	<<locked>>	87%	43555	88%	**02	97%
[IMR 4166 Enduron]*	<<locked>>	87%	44237	90%	**72	93%
[IMR 4350]*	<<locked>>	94%	44092	89%	**12	92%
[IMR 4451 Enduron]*	<<locked>>	89%	43569	88%	**89	92%
IMR 4831	<<locked>>	97%	40089	81%	**86	95%
IMR 4895	<<locked>>	84%	44367	90%	**77	98%
Lovex S062	<<locked>>	85%	44367	90%	**22	99%
[Lovex S065]*	<<locked>>	91%	43961	89%	**02	94%
[Lovex S070]*	<<locked>>	93%	44106	89%	**22	93%
Norma 203B	<<locked>>	85%	44324	90%	**58	97%
Norma URP	<<locked>>	95%	43526	88%	**81	96%
Ramshot Big Game	<<locked>>	85%	43758	89%	**71	97%
[Ramshot Hunter]*	<<locked>>	95%	43787	89%	**77	94%
ReloadSwiss RS 14	<<locked>>	96%	33402	68%	**28	100%
[ReloadSwiss RS 50]*	<<locked>>	86%	44121	89%	**05	93%
ReloadSwiss RS 52 👍	<<locked>>	86%	44295	90%	**04	99%
ReloadSwiss RS 60 👍	<<locked>>	92%	44179	90%	**66	99%
ReloadSwiss RS 62	<<locked>>	95%	44034	89%	**20	96%
ReloadSwiss RS 70	<<locked>>	95%	44135	89%	**17	95%
Rottweil R 902	<<locked>>	84%	43845	89%	**95	98%
Rottweil R 903	<<locked>>	89%	43816	89%	**45	98%
[Rottweil R 907]*	<<locked>>	90%	43859	89%	**89	92%
SNPE Vectan SP 11	<<locked>>	88%	43743	89%	**71	97%
SNPE Vectan Tubal 5000	<<locked>>	87%	44063	89%	**46	100%
[SNPE Vectan Tubal 7000]*	<<locked>>	92%	44005	89%	**53	93%
[Shooters World Long Rifle]*	<<locked>>	91%	43961	89%	**02	94%
Shooters World Precision	<<locked>>	85%	44367	90%	**22	99%
Somchem S355	<<locked>>	88%	43729	89%	**28	98%
Somchem S365 👍	<<locked>>	97%	42032	85%	**97	99%
Vihtavuori N133	<<locked>>	83%	44179	90%	**46	100%
Vihtavuori N135	<<locked>>	90%	44237	90%	**02	100%
Vihtavuori N140	<<locked>>	84%	44077	89%	**92	100%
Vihtavuori N150	<<locked>>	94%	44222	90%	**12	99%
Vihtavuori N160	<<locked>>	92%	43627	88%	**31	96%
Vihtavuori N540	<<locked>>	84%	43947	89%	**09	100%
Vihtavuori N550	<<locked>>	92%	43874	89%	**84	96%
[Vihtavuori N555]*	<<locked>>	96%	34693	70%	**17	93%
Winchester 6.5 StaBALL	<<locked>>	93%	43743	89%	**12	98%
[Winchester 760]*	<<locked>>	90%	44019	89%	**81	93%

Max Load - Barrel Length: 23.60''

Powder	Charge	FR	MaxP	%	V(0)	z
[ADI AR 2208]*	<<locked>>	81%	37043	75%	**54	94%
[Accurate 2700]*	<<locked>>	85%	40727	83%	**61	90%
Accurate 4064	<<locked>>	81%	37565	76%	**90	99%
[Accurate 4350]*	<<locked>>	85%	30647	62%	**49	90%
Alliant Reloder- TS 15.5	<<locked>>	81%	36143	73%	**61	96%
Alliant Reloder-15	<<locked>>	81%	39059	79%	**36	95%
[Alliant Reloder-16]*	<<locked>>	84%	31546	64%	**69	90%
[Alliant Reloder-17]*	<<locked>>	81%	31430	64%	**92	93%
[Alliant Reloder-23]*	<<locked>>	92%	28572	58%	**90	90%
[Hodgdon CFE223]*	<<locked>>	81%	37449	76%	**30	94%
[Hodgdon H380]*	<<locked>>	81%	36941	75%	**64	93%
[Hodgdon H414]*	<<locked>>	86%	38116	77%	**33	90%
[Hodgdon H4350]*	<<locked>>	93%	40393	82%	**30	90%
[Hodgdon Hybrid 100V]*	<<locked>>	83%	27514	56%	**15	90%
[Hodgdon LVR]*	<<locked>>	83%	32387	66%	**82	90%
[Hodgdon VARGET]*	<<locked>>	81%	36709	74%	**44	94%
Hodgdon TrailBoss	<<locked>>	81%	26353	53%	**21	100%
IMR 3031	<<locked>>	81%	39653	80%	**72	100%
[IMR 4064]*	<<locked>>	81%	36158	73%	**25	94%
[IMR 4166 Enduron]*	<<locked>>	83%	38377	78%	**31	90%
[IMR 4350]*	<<locked>>	91%	39987	81%	**17	90%
[IMR 4451 Enduron]*	<<locked>>	85%	38580	78%	**67	90%
[IMR 4831]*	<<locked>>	88%	30269	61%	**20	90%
IMR 4895	<<locked>>	81%	39914	81%	**76	96%
Lovex S062	<<locked>>	81%	38392	78%	**94	97%
[Lovex S065]*	<<locked>>	83%	33663	68%	**46	90%
[Lovex S070]*	<<locked>>	88%	37463	76%	**61	90%
Norma 203B	<<locked>>	81%	38305	78%	**17	96%
[Norma URP]*	<<locked>>	84%	31154	63%	**56	90%
Ramshot Big Game	<<locked>>	81%	38000	77%	**33	95%
[Ramshot Hunter]*	<<locked>>	90%	36593	74%	**97	90%
ReloadSwiss RS 14	<<locked>>	81%	26789	54%	**67	100%
[ReloadSwiss RS 50]*	<<locked>>	81%	37492	76%	**51	91%
ReloadSwiss RS 52	<<locked>>	81%	37231	75%	**43	97%
[ReloadSwiss RS 60]*	<<locked>>	81%	30632	62%	**76	93%
[ReloadSwiss RS 62]*	<<locked>>	86%	32285	65%	**08	90%
[ReloadSwiss RS 70]*	<<locked>>	88%	35346	72%	**77	90%
Rottweil R 902	<<locked>>	81%	40350	82%	**20	98%
Rottweil R 903	<<locked>>	81%	33794	69%	**05	95%
[Rottweil R 907]*	<<locked>>	87%	39537	80%	**90	90%
[SNPE Vectan SP 11]*	<<locked>>	81%	34838	71%	**58	94%
SNPE Vectan Tubal 5000	<<locked>>	81%	36201	73%	**76	99%
[SNPE Vectan Tubal 7000]*	<<locked>>	87%	37898	77%	**15	90%
[Shooters World Long Rifle]*	<<locked>>	83%	33663	68%	**46	90%
Shooters World Precision	<<locked>>	81%	38392	78%	**94	97%
Somchem S355	<<locked>>	81%	34664	70%	**15	95%
[Somchem S365]*	<<locked>>	81%	25063	51%	**85	90%
Vihtavuori N133	<<locked>>	81%	41553	84%	**97	100%
Vihtavuori N135	<<locked>>	81%	33315	68%	**66	99%
Vihtavuori N140	<<locked>>	81%	39682	80%	**00	100%
Vihtavuori N150	<<locked>>	81%	29530	60%	**54	95%
[Vihtavuori N160]*	<<locked>>	82%	31140	63%	**17	90%
Vihtavuori N540	<<locked>>	81%	39624	80%	**20	99%
[Vihtavuori N550]*	<<locked>>	82%	31372	64%	**62	90%
[Vihtavuori N555]*	<<locked>>	91%	29327	59%	**49	90%
[Winchester 6.5 StaBALL]*	<<locked>>	81%	29573	60%	**38	92%
[Winchester 760]*	<<locked>>	86%	38116	77%	**33	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