Load data for .256 Mag. Gibbs + .257 | 90gr | Hornady GMX

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

Load Specifications

(Use the Personalized Load Calculator below to adjust )

Bullet:	.257 \| 90gr \| Hornady GMX
Manufacturer SKU:	22410
Bullet Weight:	90gr \| 5.8g
Bullet Diameter:	0.257" \| 6.53mm
Bullet Length:	1.220" \| 31.0mm
Caliber:	.256 Mag. Gibbs load data
Case Length (l3):	2.173" \| 55.2mm
Cartridge Length (C.O.L.):	3.004" \| 76.3mm
Seated Depth:	0.389" \| 9.9mm
Shank Seated Depth:	0.329" \| 8.4mm
Case Capacity:	56.0 Grains of Water \| 3.64 cm³
Primer Size:	Large Rifle (LR)
Max. allowed Pressure:	49313 psi \| 3400 bar
LID:	LID_B2565_C231
Last updated:	2025-01-01
Recommended Twist Rate:	1:8 - 1:7

Load data for 108 loads in caliber .256 Mag. Gibbs with .257 | 90gr | Hornady GMX bullet and 54 powders such as ReloadSwiss RS 52, ReloadSwiss RS 60. 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>>	88%	43961	89%	**99	96%
Accurate 4064	<<locked>>	87%	43787	89%	**22	100%
Accurate 4350	<<locked>>	96%	44251	90%	**84	96%
Alliant Reloder- TS 15.5	<<locked>>	88%	43526	88%	**22	98%
Alliant Reloder-15	<<locked>>	86%	44019	89%	**41	97%
Alliant Reloder-16	<<locked>>	96%	44179	90%	**97	96%
Alliant Reloder-17	<<locked>>	92%	43627	88%	**14	97%
Hodgdon CFE223	<<locked>>	86%	43714	89%	**61	96%
Hodgdon H380	<<locked>>	87%	44048	89%	**25	95%
[Hodgdon H414]*	<<locked>>	91%	43787	89%	**54	92%
Hodgdon Hybrid 100V	<<locked>>	97%	40857	83%	**86	97%
Hodgdon LVR	<<locked>>	94%	44251	90%	**64	95%
Hodgdon VARGET	<<locked>>	88%	43961	89%	**99	96%
Hodgdon TrailBoss	<<locked>>	97%	33344	68%	**72	100%
IMR 3031	<<locked>>	85%	43816	89%	**54	100%
IMR 4064	<<locked>>	88%	43439	88%	**76	96%
[IMR 4166 Enduron]*	<<locked>>	88%	44179	90%	**46	92%
[IMR 4451 Enduron]*	<<locked>>	90%	43656	89%	**69	92%
[IMR 4831]*	<<locked>>	97%	38348	78%	**27	94%
IMR 4895	<<locked>>	85%	43990	89%	**51	97%
Lovex D073.6	<<locked>>	84%	44382	90%	**31	99%
Lovex S062	<<locked>>	86%	44324	90%	**15	98%
[Lovex S065]*	<<locked>>	92%	43656	89%	**82	94%
[Lovex S070]*	<<locked>>	94%	43947	89%	**09	93%
Norma 203B	<<locked>>	86%	44193	90%	**51	97%
Norma URP	<<locked>>	96%	44280	90%	**77	96%
Ramshot Big Game	<<locked>>	86%	43511	88%	**41	97%
[Ramshot Hunter]*	<<locked>>	96%	43801	89%	**61	93%
ReloadSwiss RS 14	<<locked>>	97%	33678	68%	**18	100%
[ReloadSwiss RS 50]*	<<locked>>	87%	43772	89%	**82	93%
ReloadSwiss RS 52 👍	<<locked>>	87%	43685	89%	**71	99%
ReloadSwiss RS 60 👍	<<locked>>	93%	44077	89%	**43	99%
ReloadSwiss RS 62	<<locked>>	96%	43453	88%	**84	95%
[ReloadSwiss RS 70]*	<<locked>>	95%	43526	88%	**84	94%
Rottweil R 902	<<locked>>	84%	43714	89%	**82	98%
Rottweil R 903	<<locked>>	90%	44034	89%	**41	98%
SNPE Vectan SP 11	<<locked>>	89%	44266	90%	**68	97%
SNPE Vectan Tubal 5000	<<locked>>	88%	43990	89%	**27	100%
[SNPE Vectan Tubal 7000]*	<<locked>>	93%	43700	89%	**27	92%
[Shooters World Long Rifle]*	<<locked>>	92%	43656	89%	**82	94%
Shooters World Match Rifle	<<locked>>	84%	44382	90%	**31	99%
Shooters World Precision	<<locked>>	86%	44324	90%	**15	98%
Somchem S355	<<locked>>	90%	44121	89%	**22	98%
Somchem S365	<<locked>>	97%	40016	81%	**35	98%
Vihtavuori N133	<<locked>>	84%	43816	89%	**23	100%
Vihtavuori N135	<<locked>>	91%	43540	88%	**82	100%
Vihtavuori N140	<<locked>>	85%	43932	89%	**82	100%
Vihtavuori N150	<<locked>>	95%	44179	90%	**99	99%
Vihtavuori N160	<<locked>>	93%	43468	88%	**22	95%
Vihtavuori N540	<<locked>>	85%	44222	90%	**12	100%
Vihtavuori N550	<<locked>>	93%	43656	89%	**61	95%
[Vihtavuori N555]*	<<locked>>	96%	33243	67%	**58	92%
Winchester 6.5 StaBALL	<<locked>>	94%	43598	88%	**95	98%
[Winchester 760]*	<<locked>>	91%	43787	89%	**54	92%

Max Load - Barrel Length: 23.60''

Powder	Charge	FR	MaxP	%	V(0)	z
[ADI AR 2208]*	<<locked>>	81%	35592	72%	**99	93%
Accurate 4064	<<locked>>	81%	35940	73%	**51	99%
[Accurate 4350]*	<<locked>>	86%	31183	63%	**56	90%
Alliant Reloder- TS 15.5	<<locked>>	81%	35244	71%	**25	95%
Alliant Reloder-15	<<locked>>	81%	37942	77%	**97	95%
[Alliant Reloder-16]*	<<locked>>	86%	32430	66%	**79	90%
[Alliant Reloder-17]*	<<locked>>	81%	30356	62%	**46	91%
[Hodgdon CFE223]*	<<locked>>	81%	36230	73%	**84	93%
[Hodgdon H380]*	<<locked>>	81%	35491	72%	**15	92%
[Hodgdon H414]*	<<locked>>	88%	39363	80%	**53	90%
[Hodgdon Hybrid 100V]*	<<locked>>	85%	27804	56%	**08	90%
[Hodgdon LVR]*	<<locked>>	85%	33634	68%	**05	90%
[Hodgdon VARGET]*	<<locked>>	81%	35592	72%	**99	93%
Hodgdon TrailBoss	<<locked>>	81%	26310	53%	**04	100%
IMR 3031	<<locked>>	81%	38130	77%	**27	100%
[IMR 4064]*	<<locked>>	81%	34911	71%	**72	93%
[IMR 4166 Enduron]*	<<locked>>	84%	39044	79%	**31	90%
[IMR 4451 Enduron]*	<<locked>>	86%	39407	80%	**67	90%
[IMR 4831]*	<<locked>>	90%	30690	62%	**23	90%
IMR 4895	<<locked>>	81%	38740	79%	**27	96%
Lovex D073.6	<<locked>>	81%	40669	82%	**59	99%
Lovex S062	<<locked>>	81%	37304	76%	**51	97%
[Lovex S065]*	<<locked>>	85%	34635	70%	**59	90%
[Lovex S070]*	<<locked>>	90%	37927	77%	**61	90%
Norma 203B	<<locked>>	81%	37318	76%	**84	95%
[Norma URP]*	<<locked>>	86%	31981	65%	**69	90%
[Ramshot Big Game]*	<<locked>>	81%	36738	74%	**84	94%
[Ramshot Hunter]*	<<locked>>	91%	37115	75%	**04	90%
ReloadSwiss RS 14	<<locked>>	81%	26803	54%	**50	100%
[ReloadSwiss RS 50]*	<<locked>>	82%	37173	75%	**25	90%
ReloadSwiss RS 52	<<locked>>	81%	35679	72%	**87	97%
[ReloadSwiss RS 60]*	<<locked>>	81%	29733	60%	**20	92%
[ReloadSwiss RS 62]*	<<locked>>	87%	32213	65%	**99	90%
[ReloadSwiss RS 70]*	<<locked>>	90%	36013	73%	**87	90%
Rottweil R 902	<<locked>>	81%	39218	80%	**81	97%
[Rottweil R 903]*	<<locked>>	81%	32416	66%	**56	94%
[SNPE Vectan SP 11]*	<<locked>>	81%	33663	68%	**05	93%
SNPE Vectan Tubal 5000	<<locked>>	81%	35157	71%	**36	99%
[SNPE Vectan Tubal 7000]*	<<locked>>	89%	38261	78%	**15	90%
[Shooters World Long Rifle]*	<<locked>>	85%	34635	70%	**59	90%
Shooters World Match Rifle	<<locked>>	81%	40669	82%	**59	99%
Shooters World Precision	<<locked>>	81%	37304	76%	**51	97%
[Somchem S355]*	<<locked>>	81%	33286	68%	**66	94%
[Somchem S365]*	<<locked>>	83%	25773	52%	**92	90%
Vihtavuori N133	<<locked>>	81%	40277	82%	**51	100%
Vihtavuori N135	<<locked>>	81%	32401	66%	**26	99%
Vihtavuori N140	<<locked>>	81%	38725	79%	**67	99%
[Vihtavuori N150]*	<<locked>>	81%	28601	58%	**08	94%
[Vihtavuori N160]*	<<locked>>	84%	32097	65%	**33	90%
Vihtavuori N540	<<locked>>	81%	38203	77%	**77	99%
[Vihtavuori N550]*	<<locked>>	84%	32314	66%	**82	91%
[Vihtavuori N555]*	<<locked>>	93%	29892	61%	**56	90%
[Winchester 6.5 StaBALL]*	<<locked>>	81%	28514	58%	**92	91%
[Winchester 760]*	<<locked>>	88%	39363	80%	**53	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